diff --git a/.github/workflows/changelog.yml b/.github/workflows/changelog.yml
new file mode 100644
index 0000000..e8f596e
--- /dev/null
+++ b/.github/workflows/changelog.yml
@@ -0,0 +1,30 @@
+name: Changelog
+
+on:
+  pull_request:
+    branches: [main]
+    paths:
+      - 'lib/**'
+      - 'tests/**'
+      - 'composer.json'
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    name: Check CHANGELOG updated
+
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Verify CHANGELOG.md was updated
+        run: |
+          git fetch origin ${{ github.base_ref }} --depth=1
+          if git diff --name-only origin/${{ github.base_ref }} HEAD | grep -q 'CHANGELOG.md'; then
+            echo "CHANGELOG.md was updated"
+            exit 0
+          else
+            echo "ERROR: CHANGELOG.md was not updated. Please document your changes."
+            exit 1
+          fi
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..d2c8132
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,81 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        php-version: ['8.1', '8.2', '8.3', '8.4']
+
+    name: PHP ${{ matrix.php-version }}
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          coverage: none
+
+      - name: Validate composer.json
+        run: composer validate --strict
+
+      - name: Cache Composer packages
+        id: composer-cache
+        uses: actions/cache@v5
+        with:
+          path: vendor
+          key: ${{ runner.os }}-php-${{ matrix.php-version }}-${{ hashFiles('**/composer.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-php-${{ matrix.php-version }}-
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress
+
+      - name: Run tests
+        run: composer test
+
+  static-analysis:
+    runs-on: ubuntu-latest
+    name: Static Analysis
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.1'
+          coverage: none
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress
+
+      - name: Run PHPStan
+        run: composer phpstan
+
+  code-style:
+    runs-on: ubuntu-latest
+    name: Code Style
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.1'
+          coverage: none
+
+      - name: Install dependencies
+        run: composer install --prefer-dist --no-progress
+
+      - name: Check code style
+        run: composer cs-check
\ No newline at end of file
diff --git a/.github/workflows/pr-summary.yml b/.github/workflows/pr-summary.yml
new file mode 100644
index 0000000..930c7b2
--- /dev/null
+++ b/.github/workflows/pr-summary.yml
@@ -0,0 +1,49 @@
+name: Auto Generate PR Summary
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  generate-summary:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: pip install requests
+
+      - name: Get PR Diff
+        run: |
+          git diff origin/${{ github.base_ref }}...HEAD > pr_diff.txt
+
+      - name: Generate Summary with Ollama Cloud
+        id: ollama
+        env:
+          OLLAMA_API_KEY: ${{ secrets.OLLAMA_API_KEY }}
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh pr view ${{ github.event.pull_request.number }} --json body -q .body > current_body.md || touch current_body.md
+          python scripts/generate_pr_summary.py pr_diff.txt current_body.md > summary.md
+
+          echo "SUMMARY<<EOF" >> $GITHUB_ENV
+          cat summary.md >> $GITHUB_ENV
+          echo "EOF" >> $GITHUB_ENV
+
+      - name: Update PR Description
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh pr edit ${{ github.event.pull_request.number }} --body "$SUMMARY"
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000..9f90fdd
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,43 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+
+jobs:
+  create-release:
+    runs-on: ubuntu-latest
+    name: Create GitHub Release
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Extract version from tag
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/}" >> "$GITHUB_OUTPUT"
+
+      - name: Extract release notes from CHANGELOG
+        id: notes
+        run: |
+          VERSION="${GITHUB_REF#refs/tags/v}"
+          # Extract section for this version from CHANGELOG.md
+          awk "/^## \\[$VERSION\\]/ {flag=1; next} /^## \\[/ {flag=0} flag" CHANGELOG.md > release_notes.md
+          if [ ! -s release_notes.md ]; then
+            echo "No release notes found for $VERSION in CHANGELOG.md"
+            exit 1
+          fi
+          echo "notes<<EOF" >> "$GITHUB_OUTPUT"
+          cat release_notes.md >> "$GITHUB_OUTPUT"
+          echo "EOF" >> "$GITHUB_OUTPUT"
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          name: ${{ steps.version.outputs.VERSION }}
+          body_path: release_notes.md
+          draft: false
+          prerelease: false
diff --git a/.gitignore b/.gitignore
index b2767ca..9c15e89 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@ vendor/
 # misc
 composer.lock
 .DS_Store
+.php-cs-fixer.cache
 
 # text editor settings
 .vscode/
diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
new file mode 100644
index 0000000..5027aed
--- /dev/null
+++ b/.php-cs-fixer.dist.php
@@ -0,0 +1,35 @@
+<?php
+
+$finder = PhpCsFixer\Finder::create()
+    ->in(__DIR__ . '/lib')
+    ->in(__DIR__ . '/tests')
+    ->in(__DIR__ . '/examples');
+
+return (new PhpCsFixer\Config())
+    ->setRules([
+        '@PSR12' => true,
+        'array_syntax' => ['syntax' => 'short'],
+        'ordered_imports' => ['sort_algorithm' => 'alpha'],
+        'no_unused_imports' => true,
+        'not_operator_with_successor_space' => true,
+        'trailing_comma_in_multiline' => true,
+        'phpdoc_scalar' => true,
+        'unary_operator_spaces' => true,
+        'binary_operator_spaces' => true,
+        'blank_line_before_statement' => [
+            'statements' => ['break', 'continue', 'declare', 'return', 'throw', 'try'],
+        ],
+        'phpdoc_single_line_var_spacing' => true,
+        'phpdoc_var_without_name' => true,
+        'class_attributes_separation' => [
+            'elements' => [
+                'method' => 'one',
+            ],
+        ],
+        'method_argument_space' => [
+            'on_multiline' => 'ensure_fully_multiline',
+            'keep_multiple_spaces_after_comma' => true,
+        ],
+        'single_trait_insert_per_statement' => true,
+    ])
+    ->setFinder($finder);
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..41fa450
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,138 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [2.0.0] - 2026-05-14
+
+### Added
+
+- Add custom exception hierarchy for API error handling (`ChipApiException`, `AuthenticationException`, `NotFoundException`, `ValidationException`, `ClientException`, `ServerException`)
+- Add PSR-3 logger injection support for request/response observability
+- Add configurable request timeout via constructor `$config` array
+- Add `PurchaseBuilder` fluent API for constructing purchase objects
+- Add PHPStan (level 8) and PHP-CS-Fixer configuration
+- Add GitHub Actions CI workflow (tests on PHP 8.1–8.3, static analysis, code style)
+- Add GitHub Actions PR summary automation via Ollama Cloud
+- Add GitHub Actions changelog validation and release automation
+- Expand test coverage: model mapping tests, exception handling tests, logger integration, timeout configuration, billing API tests, webhook verification tests
+- Add new endpoints and models: Account (balance, turnover), PublicKey, Statements, Client CRUD, Webhook list/update, Purchase resend invoice
+- Add `ClientRecurringToken`, `ClientRecurringTokenList`, `CompanyStatement`, `CompanyStatementList`, `WebhookList` models
+- Add `Chip\Http\ClientInterface` internal HTTP abstraction with `GuzzleClient` implementation
+- Add `RetryClient` decorator with exponential backoff for 429/5xx responses
+- Add resource classes: `PurchasesResource`, `ClientsResource`, `WebhooksResource`, `PaymentMethodsResource`, `AccountResource`, `StatementsResource`, `PublicKeyResource`, `BillingResource`
+- Add `fromArray()` static factory methods to all models replacing JsonMapper
+- Add pagination iterators (`iterate()`, `iterateTemplates()`, `iterateClients()`) for list endpoints
+
+### Changed
+
+- **Bump PHP requirement from `>=7.2.0` to `^8.1`**
+- **Rewrite `ChipApi` from trait-based architecture to resource-based architecture** (`$chip->purchases->create()` instead of `$chip->createPurchase()`)
+- **Replace JsonMapper with typed `fromArray()` static factory methods on all models**
+- **Add automatic retry with exponential backoff for 429 and 5xx responses**
+- **Rewrite `ChipApi::request()` to catch Guzzle HTTP exceptions and throw domain-specific exceptions**
+- Upgrade PHPUnit to ^10.5, PHPStan to ^2.1, PHP-CS-Fixer to ^3.95
+- Rewrite README with badges, quick-start, API reference, error handling docs
+- Rewrite MIGRATION.md with resource API migration guide and pagination docs
+- Add CONTRIBUTING.md with development workflow guidelines
+- Update CLAUDE.md with new commands and architecture details
+
+### Removed
+
+- Remove `netresearch/jsonmapper` dependency
+- Remove `Chip\Traits\Api\*` traits (`Purchase`, `PaymentMethod`, `Client`, `Webhook`, `Billing`, `PublicKey`, `Account`, `Statements`)
+
+### Fixed
+
+- Fix implicitly nullable parameter warnings in `Purchase` trait by using explicit nullable types (`?int`)
+- Fix existing tests to pass correct types (string IDs, `Purchase` objects)
+- Add property and return types to billing models and traits for PHPStan level 8 compliance
+- Fix composer.json missing required `description` field for strict validation
+- Fix model properties to match OpenAPI spec: `Product::quantity`, `Product::tax_percent` are now `string|null`; `Purchase::issued` is now `string|null`; `Purchase::status_history` is now `array`
+
+## [1.1.3] - 2024-03-12
+
+### Fixed
+
+- Fix logo not appearing for get payment method
+- Fix indentation in billing template client subscriber
+
+## [1.1.2] - 2024-02-13
+
+### Added
+
+- Add billing traits and billing models
+- Add `markAsPaid` method for purchases
+- Add `BillingTemplateClientAddSubscriber` model
+- Add sample test files and test cases
+
+### Changed
+
+- Update API methods and models
+- Refactor billing-related code
+
+## [1.1.1] - 2023-04-06
+
+### Added
+
+- Add webhook delete API
+
+### Changed
+
+- Amend PHP version requirement in README
+
+## [1.1.0] - 2023-04-05
+
+### Added
+
+- Add webhooks API (create and get)
+- Add `PaymentMethod` model
+
+### Changed
+
+- Refactor code for PHP 8 compatibility
+- Bump PHP version requirement to at least 8.0.0
+
+### Fixed
+
+- Fix `payment_method_whitelist` typo
+- Ensure non-null values are included via `array_filter`
+
+## [1.0.1] - 2023-02-13
+
+### Added
+
+- Add `force_recurring` property to `Purchase` model
+- Add `createClient` method in `Client` trait
+
+### Changed
+
+- Load VCS instead of package to ensure `composer.json` file is readable
+- Update README with installation instructions
+
+### Fixed
+
+- Add missing `require` for `chip-sdk-php` in composer examples
+
+## [1.0.0] - 2023-01-05
+
+### Added
+
+- Initial release
+- `ChipApi` client with `Purchase`, `PaymentMethod`, `Client`, and `Webhook` traits
+- Models: `Purchase`, `PurchaseDetails`, `Product`, `ClientDetails`, `PaymentMethods`, `Webhook`
+- `verify()` static method for webhook signature verification using RSA-SHA256
+- Basic test suite with Guzzle `MockHandler`
+
+[Unreleased]: https://github.com/CHIPAsia/chip-php-sdk/compare/v2.0.0...HEAD
+[2.0.0]: https://github.com/CHIPAsia/chip-php-sdk/compare/v1.1.3...v2.0.0
+[1.1.3]: https://github.com/CHIPAsia/chip-php-sdk/compare/v1.1.2...v1.1.3
+[1.1.2]: https://github.com/CHIPAsia/chip-php-sdk/compare/v1.1.1...v1.1.2
+[1.1.1]: https://github.com/CHIPAsia/chip-php-sdk/compare/v1.1.0...v1.1.1
+[1.1.0]: https://github.com/CHIPAsia/chip-php-sdk/compare/v1.0.1...v1.1.0
+[1.0.1]: https://github.com/CHIPAsia/chip-php-sdk/compare/v1.0.0...v1.0.1
+[1.0.0]: https://github.com/CHIPAsia/chip-php-sdk/releases/tag/v1.0.0
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..3b06886
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,55 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Commands
+
+- Install dependencies: `composer install`
+- Run all tests: `composer test` (or `./vendor/bin/phpunit tests`)
+- Run a single test: `./vendor/bin/phpunit tests/ApiTest.php --filter testRefundWithoutAmount`
+- Run static analysis: `composer phpstan`
+- Fix code style: `composer cs-fix`
+- Check code style without fixing: `composer cs-check`
+
+## Architecture
+
+`ChipApi` (`lib/ChipApi.php`) is the main client class. It composes API functionality through four traits in `lib/Traits/Api/`:
+
+- `Purchase` — create, get, cancel, release, capture, charge, refund purchases, and delete recurring tokens
+- `PaymentMethod` — list available payment methods for a brand/currency
+- `Client` — create clients
+- `Webhook` — create and get webhooks
+
+All API methods use the protected `request()` helper on `ChipApi`, which sends authenticated Guzzle HTTP requests and returns decoded JSON. Results are mapped to model objects via `JsonMapper` (`netresearch/jsonmapper`).
+
+### Error Handling
+
+`request()` catches Guzzle HTTP exceptions and throws domain-specific exceptions in `lib/Exception/`:
+
+- `AuthenticationException` — 401 responses
+- `NotFoundException` — 404 responses
+- `ValidationException` — 422 responses (exposes validation errors via `getErrors()`)
+- `ServerException` — 5xx responses
+- `ClientException` — other 4xx responses
+
+All exceptions extend `ChipApiException`, which exposes the decoded response body via `getResponseBody()`.
+
+### Models
+
+Models live in `lib/Model/` and are plain POPO classes with public properties, implementing `JsonSerializable`. Serialization strips null values via `array_filter((array) $this)`. The main models are `Purchase`, `PurchaseDetails`, `Product`, `ClientDetails`, `PaymentMethods`, and `Webhook`.
+
+### Builders
+
+`PurchaseBuilder` (`lib/Builder/PurchaseBuilder.php`) provides a fluent API for constructing `Purchase` objects without manually nesting `ClientDetails`, `PurchaseDetails`, and `Product` instances.
+
+### Logging & Configuration
+
+`ChipApi` accepts an optional `Psr\Log\LoggerInterface` for request/response logging, and an optional `timeout` key in the `$config` array (defaults to 30 seconds).
+
+### Testing
+
+Tests in `tests/ApiTest.php` use Guzzle's `MockHandler` and `Middleware::history()` to intercept and assert on HTTP requests without making real network calls. The helper `getMockApi()` constructs a `ChipApi` instance injected with a custom Guzzle handler stack.
+
+### Webhook Verification
+
+`ChipApi::verify()` is a static utility that verifies RSA-SHA256 signatures on webhook/callback payloads using `openssl_verify`.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..29ab001
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,76 @@
+# Contributing to CHIP PHP SDK
+
+Thank you for your interest in contributing! We welcome bug reports, feature requests, and pull requests.
+
+## Getting Started
+
+1. Fork the repository
+2. Clone your fork: `git clone git@github.com:your-username/chip-php-sdk.git`
+3. Install dependencies: `composer install`
+4. Run tests: `composer test`
+
+## Development Workflow
+
+### Running Tests
+
+```bash
+# Run all tests
+composer test
+
+# Run a specific test
+./vendor/bin/phpunit tests/ApiTest.php --filter testCreatePurchase
+```
+
+### Static Analysis
+
+We use PHPStan at level 8. All code must pass:
+
+```bash
+composer phpstan
+```
+
+### Code Style
+
+We use PHP-CS-Fixer with the PSR-12 preset. Check style before committing:
+
+```bash
+composer cs-check
+```
+
+Auto-fix issues:
+
+```bash
+composer cs-fix
+```
+
+If you need to run php-cs-fixer on PHP 8.0 (e.g., for CI compatibility):
+
+```bash
+docker run --rm -v "$(pwd)":/app -w /app php:8.0-cli bash -c "
+  ./vendor/bin/php-cs-fixer fix --dry-run --diff --config=.php-cs-fixer.dist.php
+"
+```
+
+## Submitting Changes
+
+1. Create a feature branch: `git checkout -b feature/my-feature`
+2. Make your changes with tests
+3. Ensure all tests pass: `composer test`
+4. Ensure PHPStan passes: `composer phpstan`
+5. Ensure code style is clean: `composer cs-check`
+6. Commit with a clear message
+7. Push and open a Pull Request
+
+## Reporting Bugs
+
+When reporting bugs, please include:
+
+- PHP version
+- SDK version
+- Steps to reproduce
+- Expected vs actual behavior
+- Stack trace if applicable
+
+## Code of Conduct
+
+Be respectful and constructive in all interactions.
diff --git a/MIGRATION.md b/MIGRATION.md
new file mode 100644
index 0000000..0fbbc8c
--- /dev/null
+++ b/MIGRATION.md
@@ -0,0 +1,242 @@
+# Migration Guide
+
+## Upgrading from 1.x to 2.0.0
+
+### PHP Version Requirement
+
+The minimum PHP version has been raised from `>=7.2.0` to `^8.1`.
+
+If your project runs on PHP 7.2–8.0, you must upgrade your runtime before installing version 2.0.0.
+
+### Exception Handling
+
+In 1.x, Guzzle HTTP exceptions bubbled up directly. In 2.0.0, `ChipApi` catches all HTTP errors and throws domain-specific exceptions.
+
+**Before (1.x):**
+
+```php
+use GuzzleHttp\Exception\ClientException;
+use GuzzleHttp\Exception\ServerException;
+
+try {
+    $purchase = $chip->getPurchase('nonexistent_id');
+} catch (ClientException $e) {
+    $statusCode = $e->getResponse()->getStatusCode();
+    $body = json_decode((string) $e->getResponse()->getBody(), true);
+}
+```
+
+**After (2.0.0):**
+
+```php
+use Chip\Exception\AuthenticationException;
+use Chip\Exception\NotFoundException;
+use Chip\Exception\ValidationException;
+use Chip\Exception\ServerException;
+use Chip\Exception\ClientException;
+
+try {
+    $purchase = $chip->purchases->get('nonexistent_id');
+} catch (NotFoundException $e) {
+    $statusCode = $e->getCode(); // 404
+    $body = $e->getResponseBody(); // decoded array
+} catch (ValidationException $e) {
+    $errors = $e->getErrors(); // 422 validation errors
+} catch (AuthenticationException $e) {
+    // 401 - invalid API key
+} catch (ServerException $e) {
+    // 5xx - server error
+} catch (ClientException $e) {
+    // other 4xx errors
+}
+```
+
+All exceptions extend `Chip\Exception\ChipApiException`, which exposes the decoded response body via `getResponseBody()`.
+
+### Model Property Type Changes
+
+Several model properties changed types to match the CHIP API specification.
+
+#### `Product`
+
+| Property | Before | After |
+|----------|--------|-------|
+| `$quantity` | `float` | `string\|null` |
+| `$tax_percent` | `float` | `string\|null` |
+
+**Before (1.x):**
+
+```php
+$product = new \Chip\Model\Product();
+$product->name = 'Widget';
+$product->price = 5000;
+$product->quantity = 2.0;
+$product->tax_percent = 0.06;
+$total = $product->price * $product->quantity; // works
+```
+
+**After (2.0.0):**
+
+```php
+$product = new \Chip\Model\Product();
+$product->name = 'Widget';
+$product->price = 5000;
+$product->quantity = '2.0';  // now a string
+$product->tax_percent = '0.06';  // now a string
+$total = $product->price * (float) $product->quantity; // cast needed
+```
+
+> The API returns `quantity` and `tax_percent` as strings (e.g. `"1.0000"`, `"0.00"`), so the model now reflects the actual response format.
+
+#### `Purchase`
+
+| Property | Before | After |
+|----------|--------|-------|
+| `$issued` | `int` | `string\|null` |
+| `$status_history` | `object` | `array` |
+
+**Before (1.x):**
+
+```php
+$issuedTimestamp = $purchase->issued; // int
+$status = $purchase->status_history->status; // object access
+```
+
+**After (2.0.0):**
+
+```php
+$issuedString = $purchase->issued; // string or null
+$status = $purchase->status_history[0]->status; // array access
+```
+
+#### `PaymentMethods`
+
+| Property | Before | After |
+|----------|--------|-------|
+| `$by_country` | `string[][]` | `array` (key-value map) |
+| `$country_names` | `string[]` | `array` (key-value map) |
+| `$names` | `string[]` | `array` (key-value map) |
+
+These are associative arrays, not sequential. Access remains the same (`$methods->names['fpx']`), but type checks may differ.
+
+### Resource-Based Client API
+
+The biggest architectural change in 2.0.0 is the move from monolithic trait-based methods on `ChipApi` to dedicated resource objects:
+
+**Before (1.x):**
+
+```php
+$purchase = $chip->createPurchase($purchase);
+$client = $chip->createClient($clientDetails);
+$webhook = $chip->createWebhook($webhook);
+$methods = $chip->getPaymentMethods('MYR');
+$balance = $chip->getBalance();
+```
+
+**After (2.0.0):**
+
+```php
+$purchase = $chip->purchases->create($purchase);
+$client = $chip->clients->create($clientDetails);
+$webhook = $chip->webhooks->create($webhook);
+$methods = $chip->paymentMethods->list('MYR');
+$balance = $chip->account->balance();
+```
+
+Available resources:
+
+| Resource | Old Method | New Method |
+|----------|-----------|------------|
+| `purchases` | `createPurchase()` | `create()` |
+| `purchases` | `getPurchase()` | `get()` |
+| `purchases` | `cancelPurchase()` | `cancel()` |
+| `purchases` | `releasePurchase()` | `release()` |
+| `purchases` | `capturePurchase()` | `capture()` |
+| `purchases` | `chargePurchase()` | `charge()` |
+| `purchases` | `refundPurchase()` | `refund()` |
+| `purchases` | `deleteRecurringToken()` | `deleteRecurringToken()` |
+| `purchases` | `markAsPaid()` | `markAsPaid()` |
+| `purchases` | `resendInvoice()` | `resendInvoice()` |
+| `clients` | `createClient()` | `create()` |
+| `clients` | `getClient()` | `get()` |
+| `clients` | `getClients()` | `list()` |
+| `clients` | `updateClient()` | `update()` |
+| `clients` | `partialUpdateClient()` | `partialUpdate()` |
+| `clients` | `deleteClient()` | `delete()` |
+| `clients` | `listRecurringTokens()` | `listRecurringTokens()` |
+| `clients` | `getRecurringToken()` | `getRecurringToken()` |
+| `clients` | `deleteRecurringTokenByClient()` | `deleteRecurringToken()` |
+| `webhooks` | `createWebhook()` | `create()` |
+| `webhooks` | `getWebhook()` | `get()` |
+| `webhooks` | `listWebhooks()` | `list()` |
+| `webhooks` | `updateWebhook()` | `update()` |
+| `webhooks` | `partialUpdateWebhook()` | `partialUpdate()` |
+| `webhooks` | `deleteWebhook()` | `delete()` |
+| `paymentMethods` | `getPaymentMethods()` | `list()` |
+| `publicKey` | `getPublicKey()` | `get()` |
+| `account` | `getBalance()` | `balance()` |
+| `account` | `getTurnover()` | `turnover()` |
+| `statements` | `scheduleStatement()` | `schedule()` |
+| `statements` | `listStatements()` | `list()` |
+| `statements` | `getStatement()` | `get()` |
+| `statements` | `cancelStatement()` | `cancel()` |
+| `billing` | `createBilling()` | `create()` |
+| `billing` | `createBillingTemplate()` | `createTemplate()` |
+| `billing` | `getBillingTemplates()` | `listTemplates()` |
+| `billing` | `getBillingTemplate()` | `getTemplate()` |
+| `billing` | `updateBillingTemplate()` | `updateTemplate()` |
+| `billing` | `deleteBillingTemplate()` | `deleteTemplate()` |
+| `billing` | `sendBillingTemplateInvoice()` | `sendInvoice()` |
+| `billing` | `addBillingTemplateSubscriber()` | `addSubscriber()` |
+| `billing` | `getBillingTemplateClients()` | `listClients()` |
+| `billing` | `getBillingTemplateClient()` | `getClient()` |
+| `billing` | `updateBillingTemplateClient()` | `updateClient()` |
+
+### Pagination Iterators
+
+List endpoints now support automatic pagination iterators:
+
+```php
+foreach ($chip->clients->iterate() as $client) {
+    echo $client->email;
+}
+
+foreach ($chip->webhooks->iterate() as $webhook) {
+    echo $webhook->title;
+}
+
+foreach ($chip->billing->iterateTemplates() as $template) {
+    echo $template->title;
+}
+```
+
+### New Optional Constructor Parameter
+
+`ChipApi` now accepts an optional PSR-3 logger as the 5th parameter:
+
+```php
+$chip = new ChipApi(
+    brandId: 'YOUR_BRAND_ID',
+    apiKey: 'YOUR_API_KEY',
+    base: 'https://gate.chip-in.asia/api/v1/',
+    config: ['timeout' => 30],
+    logger: $psr3Logger // optional, new in 2.0.0
+);
+```
+
+Existing 3-argument constructor calls remain backward-compatible.
+
+### New Features Available
+
+Version 2.0.0 adds several new endpoints and helpers that were not available in 1.x:
+
+- `PurchaseBuilder` fluent API
+- `Account` endpoints: `$chip->account->balance()`, `$chip->account->turnover()`
+- `PublicKey` endpoint: `$chip->publicKey->get()`
+- `Statements` endpoints: `$chip->statements->schedule()`, `$chip->statements->list()`, `$chip->statements->get()`, `$chip->statements->cancel()`
+- Expanded `Client` endpoints: `$chip->clients->get()`, `$chip->clients->update()`, `$chip->clients->partialUpdate()`, `$chip->clients->delete()`, `$chip->clients->listRecurringTokens()`, `$chip->clients->getRecurringToken()`, `$chip->clients->deleteRecurringToken()`
+- Expanded `Webhook` endpoints: `$chip->webhooks->list()`, `$chip->webhooks->update()`, `$chip->webhooks->partialUpdate()`
+- `$chip->purchases->resendInvoice()`
+- Automatic retry with exponential backoff for 429 and 5xx responses
+
+These are purely additive — no existing code needs to change unless you want to use them.
diff --git a/README.md b/README.md
index c865807..e1e79f8 100644
--- a/README.md
+++ b/README.md
@@ -1,105 +1,406 @@
-# Chip PHP library
+# CHIP PHP SDK
+
+[![CI](https://github.com/CHIPAsia/chip-php-sdk/actions/workflows/ci.yml/badge.svg)](https://github.com/CHIPAsia/chip-php-sdk/actions)
+<!-- Packagist badges - uncomment once published:
+[![Latest Stable Version](https://poser.pugx.org/chip/chip-sdk-php/v/stable)](https://packagist.org/packages/chip/chip-sdk-php)
+[![License](https://poser.pugx.org/chip/chip-sdk-php/license)](https://packagist.org/packages/chip/chip-sdk-php)
+-->
+
+Official PHP SDK for [CHIP](https://chip-in.asia) payment platform.
 
 ## Requirements
 
-PHP 8.0 and later.
+- PHP ^8.1
+- Extensions: `curl`, `json`, `openssl`
 
-The following PHP extensions are required:
+## Upgrading from 1.x
 
-* curl
-* json
-* openssl
+See [MIGRATION.md](MIGRATION.md) for a detailed guide on breaking changes when upgrading from 1.x to 2.0.0.
 
 ## Prerequisite
-Before you start, make sure you already have created `Brand ID` and `API Key` from your developer dashboard by logging-in into [merchant portal](https://gate.chip-in.asia/login).
 
+Before you start, make sure you already have created `Brand ID` and `API Key` from your developer dashboard by logging-in into [merchant portal](https://gate.chip-in.asia/login).
 
 ## Installation
-## Composer
-
-Add the following on your `composer.json`
-```php
-"repositories": [
-  ...
-  {
-      "type": "vcs",
-      "url": "git@github.com:CHIPAsia/chip-php-sdk.git"
-  }
-],
-"require": {
-    "chip/chip-sdk-php": "^1.0"
+
+The package is not yet published on Packagist. Install via VCS repository:
+
+```bash
+composer config repositories.chip-sdk vcs https://github.com/CHIPAsia/chip-php-sdk.git
+composer require chip/chip-sdk-php:^2.0
+```
+
+## Quick Start
+
+```php
+use Chip\ChipApi;
+use Chip\Builder\PurchaseBuilder;
+
+$chip = new ChipApi('YOUR_BRAND_ID', 'YOUR_API_KEY');
+
+$purchase = PurchaseBuilder::create()
+    ->brandId('YOUR_BRAND_ID')
+    ->currency('MYR')
+    ->language('en')
+    ->clientEmail('customer@example.com')
+    ->clientFullName('John Doe')
+    ->addProduct('Widget', 5000, 2)
+    ->successRedirect('https://yourdomain.com/success')
+    ->failureRedirect('https://yourdomain.com/failure')
+    ->successCallback('https://yourdomain.com/webhook')
+    ->build();
+
+$result = $chip->purchases->create($purchase);
+
+if ($result->checkout_url) {
+    header('Location: ' . $result->checkout_url);
+    exit;
 }
 ```
 
-And run command
-```bash
-composer install
-# OR
-composer update
+## Authentication
+
+You need a `Brand ID` and `API Key` from the [CHIP Merchant Portal](https://gate.chip-in.asia/login).
+
+```php
+$chip = new ChipApi('YOUR_BRAND_ID', 'YOUR_API_KEY');
 ```
 
-## Functions
+Optional parameters:
+
+```php
+$chip = new ChipApi(
+    brandId: 'YOUR_BRAND_ID',
+    apiKey: 'YOUR_API_KEY',
+    base: 'https://gate.chip-in.asia/api/v1/', // optional, default shown
+    config: ['timeout' => 30],                  // optional Guzzle config
+    logger: $psr3Logger                         // optional PSR-3 logger
+);
+```
+
+## API Methods
+
+The SDK is organized into resource objects accessed via properties on `ChipApi`:
+
+- `$chip->purchases`
+- `$chip->clients`
+- `$chip->webhooks`
+- `$chip->paymentMethods`
+- `$chip->account`
+- `$chip->statements`
+- `$chip->publicKey`
+- `$chip->billing`
+
+### Purchases
+
+```php
+// Create a purchase
+$purchase = $chip->purchases->create($purchaseModel);
+
+// Get purchase details
+$purchase = $chip->purchases->get('purchase_id');
+
+// Cancel a purchase
+$purchase = $chip->purchases->cancel('purchase_id');
+
+// Release a purchase
+$purchase = $chip->purchases->release('purchase_id');
+
+// Capture payment (full or partial)
+$purchase = $chip->purchases->capture('purchase_id');
+$purchase = $chip->purchases->capture('purchase_id', 5000); // partial
+
+// Refund (full or partial)
+$purchase = $chip->purchases->refund('purchase_id');
+$purchase = $chip->purchases->refund('purchase_id', 2500); // partial
+
+// Charge with recurring token
+$purchase = $chip->purchases->charge('purchase_id', 'recurring_token');
+
+// Delete recurring token
+$purchase = $chip->purchases->deleteRecurringToken('purchase_id');
+
+// Resend invoice
+$purchase = $chip->purchases->resendInvoice('purchase_id');
+```
+
+### Payment Methods
+
+```php
+$methods = $chip->paymentMethods->list('MYR');
+
+// Optional filters
+$methods = $chip->paymentMethods->list('MYR', [
+    'country' => 'MY',
+    'recurring' => true,
+    'amount' => 500,
+]);
+```
+
+### Clients
+
+```php
+// Create a client
+$client = new \Chip\Model\ClientDetails();
+$client->email = 'customer@example.com';
+$client->full_name = 'John Doe';
+$created = $chip->clients->create($client);
+
+// List all clients
+$clients = $chip->clients->list();
+
+// Iterate all clients (auto-paginates)
+foreach ($chip->clients->iterate() as $client) {
+    echo $client->email;
+}
+
+// Retrieve a client
+$client = $chip->clients->get($clientId);
+
+// Update a client
+$updated = $chip->clients->update($clientId, $client);
+
+// Partially update a client
+$updated = $chip->clients->partialUpdate($clientId, $client);
+
+// Delete a client
+$chip->clients->delete($clientId);
+
+// List recurring tokens for a client
+$tokens = $chip->clients->listRecurringTokens($clientId);
+
+// Get a specific recurring token
+$token = $chip->clients->getRecurringToken($clientId, $purchaseId);
+
+// Delete a recurring token
+$chip->clients->deleteRecurringToken($clientId, $purchaseId);
+```
+
+### Webhooks
+
+```php
+// List all webhooks
+$webhooks = $chip->webhooks->list();
+
+// Iterate all webhooks (auto-paginates)
+foreach ($chip->webhooks->iterate() as $webhook) {
+    echo $webhook->title;
+}
+
+// Create a webhook
+$webhook = new \Chip\Model\Webhook();
+$webhook->title = 'My Webhook';
+$webhook->callback = 'https://yourdomain.com/webhook';
+$created = $chip->webhooks->create($webhook);
+
+// Get webhook details
+$webhook = $chip->webhooks->get($webhookId);
 
-**getPaymentMethods**
+// Update a webhook
+$updated = $chip->webhooks->update($webhookId, $webhook);
+
+// Partially update a webhook
+$updated = $chip->webhooks->partialUpdate($webhookId, $webhook);
+
+// Delete a webhook
+$chip->webhooks->delete($webhookId);
 ```
-Get list of payment methods that available for your account.
+
+### Account
+
+```php
+// Get account balance (with optional filters)
+$balance = $chip->account->balance();
+$balance = $chip->account->balance(['currency' => 'MYR']);
+
+// Get account turnover
+$turnover = $chip->account->turnover(['from' => 1609459200, 'to' => 1640995200]);
 ```
 
-**createPurchase**
+### Statements
+
+```php
+// Schedule a company statement
+$statement = new \Chip\Model\CompanyStatement();
+$statement->format = 'csv';
+$scheduled = $chip->statements->schedule($statement);
+
+// List statements
+$statements = $chip->statements->list();
+
+// Iterate statements (auto-paginates)
+foreach ($chip->statements->iterate() as $statement) {
+    echo $statement->format;
+}
+
+// Get a statement
+$statement = $chip->statements->get($statementId);
+
+// Cancel a statement
+$statement = $chip->statements->cancel($statementId);
 ```
-Create checkout & direct post URL.
+
+### Public Key
+
+```php
+$publicKey = $chip->publicKey->get();
 ```
 
-**getPurchase**
+### Billing
+
+```php
+// Create a billing template
+$template = new \Chip\Model\Billing\BillingTemplate();
+$template->title = 'Monthly Subscription';
+$created = $chip->billing->createTemplate($template);
+
+// List billing templates
+$templates = $chip->billing->listTemplates();
+
+// Iterate billing templates (auto-paginates)
+foreach ($chip->billing->iterateTemplates() as $template) {
+    echo $template->title;
+}
+
+// Get a billing template
+$template = $chip->billing->getTemplate($templateId);
+
+// Update a billing template
+$updated = $chip->billing->updateTemplate($templateId, $template);
+
+// Delete a billing template
+$chip->billing->deleteTemplate($templateId);
+
+// Send an invoice from a billing template
+$client = new \Chip\Model\Billing\BillingTemplateClient();
+$client->client_id = $clientId;
+$purchase = $chip->billing->sendInvoice($templateId, $client);
+
+// Add a subscriber
+$result = $chip->billing->addSubscriber($templateId, $client);
+
+// List billing template clients
+$clients = $chip->billing->listClients($templateId);
+
+// Iterate billing template clients (auto-paginates)
+foreach ($chip->billing->iterateClients($templateId) as $client) {
+    echo $client->client_id;
+}
+
+// Get a billing template client
+$client = $chip->billing->getClient($templateId, $clientId);
+
+// Update a billing template client
+$updated = $chip->billing->updateClient($templateId, $clientId, $client);
 ```
-Get purchase detail by its ID
+
+## Error Handling
+
+The SDK throws domain-specific exceptions:
+
+```php
+use Chip\Exception\AuthenticationException;
+use Chip\Exception\NotFoundException;
+use Chip\Exception\ValidationException;
+use Chip\Exception\ServerException;
+use Chip\Exception\ClientException;
+
+try {
+    $purchase = $chip->purchases->get('nonexistent_id');
+} catch (NotFoundException $e) {
+    // 404 - Purchase not found
+    echo $e->getMessage();
+} catch (AuthenticationException $e) {
+    // 401 - Invalid API key
+} catch (ValidationException $e) {
+    // 422 - Validation failed
+    print_r($e->getErrors());
+} catch (ServerException $e) {
+    // 5xx - Server error
+} catch (ClientException $e) {
+    // Other 4xx errors
+}
 ```
 
-**verify**
+All exceptions extend `ChipApiException` and expose the response body:
+
+```php
+try {
+    $chip->purchases->create($purchase);
+} catch (ChipApiException $e) {
+    $statusCode = $e->getCode();
+    $responseBody = $e->getResponseBody();
+}
 ```
-Verify callback or webhook response from our server. For webhook public key, it is generated when you register your webhook URL. Refer to our API (https://developer.chip-in.asia/api) for more information.
+
+## Webhook Verification
+
+Verify webhook signatures using your public key:
+
+```php
+$isValid = ChipApi::verify($jsonPayload, $signatureHeader, $publicKey);
 ```
 
-And more which you can refer to [`/lib/ChipApi.php`](./lib/ChipApi.php) for more information.
+## Purchase Builder
+
+The `PurchaseBuilder` provides a fluent API for constructing purchases:
+
+```php
+use Chip\Builder\PurchaseBuilder;
 
-## Getting Started
+$purchase = PurchaseBuilder::create()
+    ->brandId('YOUR_BRAND_ID')
+    ->currency('MYR')
+    ->language('en')
+    ->clientEmail('customer@example.com')
+    ->clientFullName('John Doe')
+    ->clientPhone('+60123456789')
+    ->addProduct('Widget', 5000, 2)
+    ->addProduct('Gadget', 3000)
+    ->successRedirect('https://yourdomain.com/success')
+    ->failureRedirect('https://yourdomain.com/failure')
+    ->successCallback('https://yourdomain.com/webhook')
+    ->cancelRedirect('https://yourdomain.com/cancel')
+    ->build();
+```
 
-Simple usage looks like:
+## Logging
 
+Pass a PSR-3 compatible logger to enable request/response logging:
 
 ```php
-<?php
-  require_once 'vendor/autoload.php';
-  $chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
-  $client = new \Chip\Model\ClientDetails();
-  $client->email = 'test@example.com';
-  $purchase = new \Chip\Model\Purchase();
-  $purchase->client = $client;
-  $details = new \Chip\Model\PurchaseDetails();
-  $product = new \Chip\Model\Product();
-  $product->name = 'Test';
-  $product->price = 100;
-  $details->products = [$product];
-  $purchase->purchase = $details;
-  $purchase->brand_id = $config['brand_id'];
-  $purchase->success_redirect = 'https://yourdomain.com/redirect.php?success=1';
-  $purchase->success_callback = 'https://yourdomain.com/callback.php?success=0';
-  $purchase->failure_redirect = 'https://yourdomain.com/redirect.php?success=0';
+use Monolog\Logger;
+use Monolog\Handler\StreamHandler;
 
-  $result = $chip->createPurchase($purchase);
+$logger = new Logger('chip');
+$logger->pushHandler(new StreamHandler('chip.log'));
 
-  if ($result && $result->checkout_url) {
-    // Redirect user to checkout
-    header("Location: " . $result->checkout_url);
-    exit;
-  }
+$chip = new ChipApi('BRAND_ID', 'API_KEY', logger: $logger);
 ```
 
-## Testing
+## Development
 
 ```bash
-./vendor/bin/phpunit tests 
+# Install dependencies
+composer install
+
+# Run tests
+composer test
+
+# Run static analysis
+composer phpstan
+
+# Check code style
+composer cs-check
+
+# Fix code style
+composer cs-fix
 ```
 
-## Example
-Check our examples [here](./examples).
+## Contributing
+
+Please see [CONTRIBUTING.md](CONTRIBUTING.md) for guidelines.
+
+## License
+
+MIT License. See [LICENSE](LICENSE) for details.
diff --git a/composer.json b/composer.json
index 65a5f05..9cf5df9 100644
--- a/composer.json
+++ b/composer.json
@@ -1,18 +1,32 @@
 {
     "name": "chip/chip-sdk-php",
+    "description": "PHP SDK for CHIP Payments API",
     "type": "library",
     "require": {
-        "php": ">=8.0.0",
-        "guzzlehttp/guzzle": "^7.0",
-        "netresearch/jsonmapper": "^4.0"
+        "php": "^8.1",
+        "guzzlehttp/guzzle": "^7.9",
+        "psr/log": "^3.0"
     },
     "license": "MIT",
-	"autoload": {
+    "autoload": {
         "psr-4": {
             "Chip\\": "lib"
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.0"
+        "phpunit/phpunit": "^10.5",
+        "phpstan/phpstan": "^2.1",
+        "friendsofphp/php-cs-fixer": "^3.95"
+    },
+    "scripts": {
+        "test": "phpunit tests",
+        "phpstan": "phpstan analyse",
+        "cs-fix": "php-cs-fixer fix",
+        "cs-check": "php-cs-fixer fix --dry-run --diff"
+    },
+    "config": {
+        "platform": {
+            "php": "8.1.0"
+        }
     }
 }
diff --git a/examples/README.md b/examples/README.md
index bc80005..4dfd13f 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -10,7 +10,7 @@
 ---
 
 ## Requirements
-* It is required `PHP` version >= 7.2
+* It is required `PHP` version >= 8.1
 * `composer` to install dependencies
 
 ## Prerequisite
@@ -21,11 +21,11 @@ You will need to replace the value on file [config.php](./config.php) with the c
 <?php
 
 return [
-	'brand_id' => '<<BRAND_ID>>',
-	'api_key' => '<<API_KEY>>',
-	'endpoint' => 'https://gate.chip-in.asia/api/v1/',
-  	'basedUrl' => '<<DOMAIN_URL>>',
-  	'webhook_public_key' => "<<WEBHOOK_PUBLIC_KEY" // SHOULD BE WRAPPED IN DOUBLE QUOTES (")
+    'brand_id' => '<<BRAND_ID>>',
+    'api_key' => '<<API_KEY>>',
+    'endpoint' => 'https://gate.chip-in.asia/api/v1/',
+    'basedUrl' => '<<DOMAIN_URL>>',
+    'webhook_public_key' => "<<WEBHOOK_PUBLIC_KEY>>" // SHOULD BE WRAPPED IN DOUBLE QUOTES (")
 ];
 ```
 
diff --git a/examples/api/account_balance.php b/examples/api/account_balance.php
new file mode 100644
index 0000000..274d647
--- /dev/null
+++ b/examples/api/account_balance.php
@@ -0,0 +1,11 @@
+<?php
+
+require_once '../vendor/autoload.php';
+
+$config = include('../config.php');
+
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+
+$balance = $chip->getBalance();
+
+echo "<pre><code>" . json_encode($balance, JSON_PRETTY_PRINT) . "</code></pre>";
diff --git a/examples/api/callback.php b/examples/api/callback.php
index e7b25c7..e2c268a 100644
--- a/examples/api/callback.php
+++ b/examples/api/callback.php
@@ -1,27 +1,20 @@
 <?php
 
-  require_once '../vendor/autoload.php';
+require_once '../vendor/autoload.php';
 
-  $config = include('../config.php');
+$config = include('../config.php');
 
-  $chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
 
-  # Option 1: Use success_callback parameter of the Purchase object
-  $post = file_get_contents('php://input'); # lib/Model/Purchase.php
-  $headers = getallheaders();
-  $xSignature = $headers["X-Signature"];
+# Use SDK instead of raw curl
+$publicKey = $chip->getPublicKey();
 
-  # GET PUBLIC KEY
-  $url = $config['endpoint'] . "public_key/";
-  $curl = curl_init($url);
-  curl_setopt($curl, CURLOPT_URL, $url);
-  curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
-  $headers = array(
-    "Authorization: Bearer " . $config['api_key'],
-  );
-  curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
-  $publicKey = json_decode(curl_exec($curl));
-  curl_close($curl);
+$post = file_get_contents('php://input');
+$headers = getallheaders();
+$xSignature = $headers['X-Signature'];
 
-  $verify = \Chip\ChipApi::verify($post, $xSignature, $publicKey);
-  error_log("/callback VERIFIED: " . ($verify ? "true" : "false"));
+$verify = \Chip\ChipApi::verify($post, $xSignature, $publicKey);
+
+$data = json_decode($post);
+error_log('/callback EVENT: ' . $data->event_type);
+error_log('/callback VERIFIED: ' . ($verify ? 'true' : 'false'));
diff --git a/examples/api/client_crud.php b/examples/api/client_crud.php
new file mode 100644
index 0000000..386a1f8
--- /dev/null
+++ b/examples/api/client_crud.php
@@ -0,0 +1,28 @@
+<?php
+
+require_once '../vendor/autoload.php';
+
+$config = include('../config.php');
+
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+
+# Create a client
+$client = new \Chip\Model\ClientDetails();
+$client->email = 'client@example.com';
+$client->full_name = 'John Doe';
+
+$created = $chip->createClient($client);
+echo "<h2>Created Client</h2>";
+echo "<pre><code>" . json_encode($created, JSON_PRETTY_PRINT) . "</code></pre>";
+
+# Get all clients
+$clients = $chip->getClients();
+echo "<h2>All Clients</h2>";
+echo "<pre><code>" . json_encode($clients, JSON_PRETTY_PRINT) . "</code></pre>";
+
+# Update client
+$clientId = $created->id;
+$client->full_name = 'Jane Doe';
+$updated = $chip->updateClient($clientId, $client);
+echo "<h2>Updated Client</h2>";
+echo "<pre><code>" . json_encode($updated, JSON_PRETTY_PRINT) . "</code></pre>";
diff --git a/examples/api/create_purchase.php b/examples/api/create_purchase.php
index fcb4595..e1a676e 100644
--- a/examples/api/create_purchase.php
+++ b/examples/api/create_purchase.php
@@ -24,7 +24,7 @@
 $result = $chip->createPurchase($purchase);
 
 if ($result && $result->checkout_url) {
-	// Redirect user to checkout
-	header("Location: " . $result->checkout_url);
-	exit;
-}
\ No newline at end of file
+    // Redirect user to checkout
+    header("Location: " . $result->checkout_url);
+    exit;
+}
diff --git a/examples/api/get_purchase.php b/examples/api/get_purchase.php
index 10baf67..e9c22d9 100644
--- a/examples/api/get_purchase.php
+++ b/examples/api/get_purchase.php
@@ -6,8 +6,9 @@
 
 $chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
 
-$purchase_id = ''; # ID of the purchase: $purchase->id;
+$purchaseId = ''; # ID of the purchase: $purchase->id;
 
-$purchase = $chip->getPurchase($purchase_id);
+$purchase = $chip->getPurchase($purchaseId);
 
-print json_encode($purchase);
\ No newline at end of file
+header('Content-Type: application/json');
+echo json_encode($purchase, JSON_PRETTY_PRINT);
diff --git a/examples/api/payment_methods.php b/examples/api/payment_methods.php
index 48bad2e..0420e5c 100644
--- a/examples/api/payment_methods.php
+++ b/examples/api/payment_methods.php
@@ -8,4 +8,4 @@
 
 $methods = $chip->getPaymentMethods();
 
-echo "<pre><code>" . json_encode($methods, JSON_PRETTY_PRINT) . "</code></pre>";
\ No newline at end of file
+echo "<pre><code>" . json_encode($methods, JSON_PRETTY_PRINT) . "</code></pre>";
diff --git a/examples/api/public_key.php b/examples/api/public_key.php
index 6a44ca6..d11cca5 100644
--- a/examples/api/public_key.php
+++ b/examples/api/public_key.php
@@ -6,18 +6,8 @@
 
 $chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
 
+# Get public key via SDK
+$publicKey = $chip->getPublicKey();
 
-# GET PUBLIC KEY
-$url = $config['endpoint'] . "public_key/";
-$curl = curl_init($url);
-curl_setopt($curl, CURLOPT_URL, $url);
-curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
-$headers = array(
-  "Authorization: Bearer " . $config['api_key'],
-);
-curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
-$publicKey = json_decode(curl_exec($curl));
-curl_close($curl);
-
-header("Content-Type: application/json");
-echo $publicKey;
+header('Content-Type: application/json');
+echo json_encode(['public_key' => $publicKey]);
diff --git a/examples/api/purchase_builder.php b/examples/api/purchase_builder.php
new file mode 100644
index 0000000..83126df
--- /dev/null
+++ b/examples/api/purchase_builder.php
@@ -0,0 +1,26 @@
+<?php
+
+require_once '../vendor/autoload.php';
+
+$config = include('../config.php');
+
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+
+# Use PurchaseBuilder for a simpler API
+$purchase = \Chip\Builder\PurchaseBuilder::new()
+    ->withBrandId($config['brand_id'])
+    ->withProduct('Test Product', 100, 1)
+    ->withClient('test@example.com', 'John Doe')
+    ->withSuccessRedirect($config['basedUrl'] . '/api/redirect.php?success=1')
+    ->withFailureRedirect($config['basedUrl'] . '/api/redirect.php?success=0')
+    ->withSuccessCallback($config['basedUrl'] . '/api/callback.php')
+    ->build();
+
+$result = $chip->createPurchase($purchase);
+
+echo "<h2>Purchase Created via Builder</h2>";
+echo "<pre><code>" . json_encode($result, JSON_PRETTY_PRINT) . "</code></pre>";
+
+if ($result && $result->checkout_url) {
+    echo "<p><a href='" . $result->checkout_url . "' target='_blank'>Go to Checkout</a></p>";
+}
diff --git a/examples/api/statements.php b/examples/api/statements.php
new file mode 100644
index 0000000..435b2b0
--- /dev/null
+++ b/examples/api/statements.php
@@ -0,0 +1,20 @@
+<?php
+
+require_once '../vendor/autoload.php';
+
+$config = include('../config.php');
+
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+
+# List all statements
+$statements = $chip->listStatements();
+echo "<h2>Statements</h2>";
+echo "<pre><code>" . json_encode($statements, JSON_PRETTY_PRINT) . "</code></pre>";
+
+# Schedule a new statement
+$statement = new \Chip\Model\CompanyStatement();
+$statement->format = 'json';
+
+$scheduled = $chip->scheduleStatement($statement);
+echo "<h2>Scheduled Statement</h2>";
+echo "<pre><code>" . json_encode($scheduled, JSON_PRETTY_PRINT) . "</code></pre>";
diff --git a/examples/api/webhook.php b/examples/api/webhook.php
index cec0858..57c1a3c 100644
--- a/examples/api/webhook.php
+++ b/examples/api/webhook.php
@@ -1,21 +1,21 @@
 <?php
 
-  require_once '../vendor/autoload.php';
+require_once '../vendor/autoload.php';
 
-  $config = include('../config.php');
+$config = include('../config.php');
 
-  $chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
 
-  # Option 1: Use success_callback parameter of the Purchase object
-  $post = file_get_contents('php://input'); # lib/Model/Purchase.php
-  $headers = getallheaders();
-  $xSignature = $headers["X-Signature"];
+# Option 1: Use success_callback parameter of the Purchase object
+$post = file_get_contents('php://input');
+$headers = getallheaders();
+$xSignature = $headers['X-Signature'];
 
-  $data = json_decode($post);
+# Get public key via SDK
+$publicKey = $chip->getPublicKey();
 
-  # GET PUBLIC KEY
-  $publicKey = $config['webhook_public_key'];
+$verify = \Chip\ChipApi::verify($post, $xSignature, $publicKey);
 
-  $verify = \Chip\ChipApi::verify($post, $xSignature, $publicKey);
-  error_log("/webhook EVENT: " . $data->event_type);
-  error_log("/webhook VERIFIED: " . ($verify ? "true" : "false"));
+$data = json_decode($post);
+error_log('/webhook EVENT: ' . $data->event_type);
+error_log('/webhook VERIFIED: ' . ($verify ? 'true' : 'false'));
diff --git a/examples/api/webhook_management.php b/examples/api/webhook_management.php
new file mode 100644
index 0000000..79cc8ef
--- /dev/null
+++ b/examples/api/webhook_management.php
@@ -0,0 +1,28 @@
+<?php
+
+require_once '../vendor/autoload.php';
+
+$config = include('../config.php');
+
+$chip = new \Chip\ChipApi($config['brand_id'], $config['api_key'], $config['endpoint']);
+
+# List all webhooks
+$webhooks = $chip->listWebhooks();
+echo "<h2>Webhooks</h2>";
+echo "<pre><code>" . json_encode($webhooks, JSON_PRETTY_PRINT) . "</code></pre>";
+
+# Create a webhook
+$webhook = new \Chip\Model\Webhook();
+$webhook->url = $config['basedUrl'] . '/api/webhook.php';
+$webhook->event_type = 'purchase.paid';
+
+$created = $chip->createWebhook($webhook);
+echo "<h2>Created Webhook</h2>";
+echo "<pre><code>" . json_encode($created, JSON_PRETTY_PRINT) . "</code></pre>";
+
+# Update webhook
+$webhookId = $created->id;
+$webhook->url = $config['basedUrl'] . '/api/callback.php';
+$updated = $chip->updateWebhook($webhookId, $webhook);
+echo "<h2>Updated Webhook</h2>";
+echo "<pre><code>" . json_encode($updated, JSON_PRETTY_PRINT) . "</code></pre>";
diff --git a/examples/composer.json b/examples/composer.json
index 1017156..bdf72d4 100644
--- a/examples/composer.json
+++ b/examples/composer.json
@@ -1,15 +1,15 @@
 {
-  "name": "chip/php-sdk-examples",
-  "type": "library",
-  "require": {
-      "chip/chip-sdk-php": "^1.0.0",
-      "php": ">=7.2.0",
-  },
-  "license": "MIT",
-  "repositories": [
-    {
-        "type": "vcs",
-        "url": "git@github.com:CHIPAsia/chip-php-sdk.git"
-    }
-  ]
+    "name": "chip/php-sdk-examples",
+    "type": "library",
+    "require": {
+        "chip/chip-sdk-php": "^2.0.0",
+        "php": ">=8.1.0"
+    },
+    "license": "MIT",
+    "repositories": [
+        {
+            "type": "vcs",
+            "url": "git@github.com:CHIPAsia/chip-php-sdk.git"
+        }
+    ]
 }
diff --git a/examples/config.php b/examples/config.php
index 5ba4fcd..81d28e5 100644
--- a/examples/config.php
+++ b/examples/config.php
@@ -1,9 +1,9 @@
 <?php
 
 return [
-	'brand_id' => '<<BRAND_ID>>',
-	'api_key' => '<<API_KEY>>',
-	'endpoint' => 'https://gate.chip-in.asia/api/v1/',
-  'basedUrl' => '<<DOMAIN_URL>>',
-  'webhook_public_key' => "<<WEBHOOK_PUBLIC_KEY" // SHOULD BE WRAPPED IN DOUBLE QUOTES (")
+    'brand_id' => '<<BRAND_ID>>',
+    'api_key' => '<<API_KEY>>',
+    'endpoint' => 'https://gate.chip-in.asia/api/v1/',
+    'basedUrl' => '<<DOMAIN_URL>>',
+    'webhook_public_key' => "<<WEBHOOK_PUBLIC_KEY>>", // SHOULD BE WRAPPED IN DOUBLE QUOTES (")
 ];
diff --git a/examples/index.php b/examples/index.php
index d68e24d..a20fddb 100644
--- a/examples/index.php
+++ b/examples/index.php
@@ -1,18 +1,36 @@
 <!DOCTYPE html>
-  <body>
-    <h1>Demo Merchant</h1>
+<html>
+<body>
+    <h1>CHIP PHP SDK Examples</h1>
 
-    <span>Sample Actions:</span>
+    <span>Purchase Flow:</span>
     <ul>
-      <li>
-        <a href="/api/payment_methods.php" target="_blank">Get Payment Methods</a>
-      </li>
-      <li>
-        <a href="/api/create_purchase.php" target="_blank">Create Checkout</a>
-      </li>
-      <li>
-        <a href="/api/public_key.php" target="_blank">Public Key</a>
-      </li>
+        <li><a href="/api/payment_methods.php" target="_blank">Get Payment Methods</a></li>
+        <li><a href="/api/create_purchase.php" target="_blank">Create Checkout</a></li>
+        <li><a href="/api/get_purchase.php" target="_blank">Get Purchase</a></li>
+        <li><a href="/api/purchase_builder.php" target="_blank">Purchase Builder</a></li>
     </ul>
-  </body>
-</html>
\ No newline at end of file
+
+    <span>Account:</span>
+    <ul>
+        <li><a href="/api/account_balance.php" target="_blank">Account Balance</a></li>
+    </ul>
+
+    <span>Clients:</span>
+    <ul>
+        <li><a href="/api/client_crud.php" target="_blank">Client CRUD</a></li>
+    </ul>
+
+    <span>Statements:</span>
+    <ul>
+        <li><a href="/api/statements.php" target="_blank">Company Statements</a></li>
+    </ul>
+
+    <span>Webhooks:</span>
+    <ul>
+        <li><a href="/api/public_key.php" target="_blank">Public Key</a></li>
+        <li><a href="/api/webhook_management.php" target="_blank">Webhook Management</a></li>
+        <li><a href="/api/webhook.php" target="_blank">Webhook Receiver</a></li>
+    </ul>
+</body>
+</html>
diff --git a/lib/Builder/PurchaseBuilder.php b/lib/Builder/PurchaseBuilder.php
new file mode 100644
index 0000000..4b35fdd
--- /dev/null
+++ b/lib/Builder/PurchaseBuilder.php
@@ -0,0 +1,121 @@
+<?php
+
+namespace Chip\Builder;
+
+use Chip\Model\ClientDetails;
+use Chip\Model\Product;
+use Chip\Model\Purchase;
+use Chip\Model\PurchaseDetails;
+
+class PurchaseBuilder
+{
+    private Purchase $purchase;
+
+    public function __construct()
+    {
+        $this->purchase = new Purchase();
+        $this->purchase->purchase = new PurchaseDetails();
+    }
+
+    public static function create(): self
+    {
+        return new self();
+    }
+
+    public function brandId(string $brandId): self
+    {
+        $this->purchase->brand_id = $brandId;
+
+        return $this;
+    }
+
+    public function currency(string $currency): self
+    {
+        $this->purchase->purchase->currency = $currency;
+
+        return $this;
+    }
+
+    public function language(string $language): self
+    {
+        $this->purchase->purchase->language = $language;
+
+        return $this;
+    }
+
+    public function successRedirect(string $url): self
+    {
+        $this->purchase->success_redirect = $url;
+
+        return $this;
+    }
+
+    public function failureRedirect(string $url): self
+    {
+        $this->purchase->failure_redirect = $url;
+
+        return $this;
+    }
+
+    public function successCallback(string $url): self
+    {
+        $this->purchase->success_callback = $url;
+
+        return $this;
+    }
+
+    public function cancelRedirect(string $url): self
+    {
+        $this->purchase->cancel_redirect = $url;
+
+        return $this;
+    }
+
+    public function clientEmail(string $email): self
+    {
+        $this->ensureClient();
+        $this->purchase->client->email = $email;
+
+        return $this;
+    }
+
+    public function clientPhone(string $phone): self
+    {
+        $this->ensureClient();
+        $this->purchase->client->phone = $phone;
+
+        return $this;
+    }
+
+    public function clientFullName(string $fullName): self
+    {
+        $this->ensureClient();
+        $this->purchase->client->full_name = $fullName;
+
+        return $this;
+    }
+
+    public function addProduct(string $name, int $price, float|string $quantity = 1.0): self
+    {
+        $product = new Product();
+        $product->name = $name;
+        $product->price = $price;
+        $product->quantity = is_string($quantity) ? $quantity : (string) $quantity;
+
+        $this->purchase->purchase->products[] = $product;
+
+        return $this;
+    }
+
+    public function build(): Purchase
+    {
+        return $this->purchase;
+    }
+
+    private function ensureClient(): void
+    {
+        if ($this->purchase->client === null) {
+            $this->purchase->client = new ClientDetails();
+        }
+    }
+}
diff --git a/lib/ChipApi.php b/lib/ChipApi.php
index 4160c68..f70d394 100644
--- a/lib/ChipApi.php
+++ b/lib/ChipApi.php
@@ -1,65 +1,85 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Chip;
 
-use Chip\Traits\Api\Purchase;
-use Chip\Traits\Api\PaymentMethod;
-use Chip\Traits\Api\Client;
-use Chip\Traits\Api\Webhook;
-use Chip\Traits\Api\Billing;
+use Chip\Http\ClientInterface;
+use Chip\Http\GuzzleClient;
+use Chip\Http\RetryClient;
+use Chip\Resource\AccountResource;
+use Chip\Resource\BillingResource;
+use Chip\Resource\ClientsResource;
+use Chip\Resource\PaymentMethodsResource;
+use Chip\Resource\PublicKeyResource;
+use Chip\Resource\PurchasesResource;
+use Chip\Resource\StatementsResource;
+use Chip\Resource\WebhooksResource;
+use Psr\Log\LoggerInterface;
 
 class ChipApi
 {
+    public readonly PurchasesResource $purchases;
+
+    public readonly ClientsResource $clients;
+
+    public readonly WebhooksResource $webhooks;
+
+    public readonly PaymentMethodsResource $paymentMethods;
+
+    public readonly PublicKeyResource $publicKey;
+
+    public readonly AccountResource $account;
+
+    public readonly StatementsResource $statements;
+
+    public readonly BillingResource $billing;
+
+    /**
+     * @param array<string, mixed> $config
+     */
+    public function __construct(
+        string $brandId,
+        string $apiKey,
+        string $base = 'https://gate.chip-in.asia/api/v1/',
+        array $config = [],
+        ?LoggerInterface $logger = null,
+    ) {
+        $httpClient = $this->createHttpClient($apiKey, $base, $config, $logger);
+
+        $this->purchases = new PurchasesResource($httpClient);
+        $this->clients = new ClientsResource($httpClient);
+        $this->webhooks = new WebhooksResource($httpClient);
+        $this->paymentMethods = new PaymentMethodsResource($httpClient, $brandId);
+        $this->publicKey = new PublicKeyResource($httpClient);
+        $this->account = new AccountResource($httpClient);
+        $this->statements = new StatementsResource($httpClient);
+        $this->billing = new BillingResource($httpClient);
+    }
+
+    /**
+     * @param array<string, mixed> $config
+     */
+    private function createHttpClient(string $apiKey, string $base, array $config, ?LoggerInterface $logger): ClientInterface
+    {
+        $guzzleClient = new GuzzleClient($apiKey, $base, $config, $logger);
+
+        return new RetryClient($guzzleClient, 3, 1.0, $logger);
+    }
 
-	use Purchase, PaymentMethod, Client, Webhook, Billing;
-
-	protected $client;
-
-	protected $mapper;
-
-	public function __construct(
-		protected string $brandId,
-		protected string  $apiKey,
-		protected string  $base = 'https://gate.chip-in.asia/api/v1/',
-		array $config = []
-	) {
-		$this->mapper = new \JsonMapper();
-		$this->mapper->bStrictNullTypes = false;
-		$this->mapper->bEnforceMapType = false;
-
-		$this->client = new \GuzzleHttp\Client(array_merge([
-			'base_uri' => $this->base,
-		], $config));
-	}
-
-	protected function request(string $method, string $endpoint, array $options = array())
-	{
-		$headers = [];
-		if ($this->apiKey) {
-			$headers['Authorization'] = 'Bearer ' . $this->apiKey;
-		}
-		$response = $this->client->request($method, $endpoint, array_merge(array(
-			'headers' => $headers
-		), $options));
-		$body = (string)$response->getBody()->getContents();
-
-		return json_decode($body);
-	}
-
-	/**
-	 * 
-	 * @param string $content
-	 * @param string $signature
-	 * @param string $publicKey
-	 * @return bool
-	 */
-	public static function verify(string $content, string $signature, string $publicKey): bool
-	{
-		return 1 === openssl_verify(
-			$content,
-			base64_decode($signature),
-			$publicKey,
-			'sha256WithRSAEncryption'
-		);
-	}
+    /**
+     * @param string $content
+     * @param string $signature
+     * @param string $publicKey
+     * @return bool
+     */
+    public static function verify(string $content, string $signature, string $publicKey): bool
+    {
+        return 1 === openssl_verify(
+            $content,
+            base64_decode($signature),
+            $publicKey,
+            'sha256WithRSAEncryption'
+        );
+    }
 }
diff --git a/lib/Exception/AuthenticationException.php b/lib/Exception/AuthenticationException.php
new file mode 100644
index 0000000..2eef631
--- /dev/null
+++ b/lib/Exception/AuthenticationException.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Chip\Exception;
+
+class AuthenticationException extends ChipApiException
+{
+}
diff --git a/lib/Exception/ChipApiException.php b/lib/Exception/ChipApiException.php
new file mode 100644
index 0000000..d971765
--- /dev/null
+++ b/lib/Exception/ChipApiException.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Chip\Exception;
+
+use Exception;
+
+class ChipApiException extends Exception
+{
+    /** @var array<string, mixed>|null */
+    protected ?array $responseBody;
+
+    /**
+     * @param array<string, mixed>|null $responseBody
+     */
+    public function __construct(string $message = '', int $code = 0, ?array $responseBody = null, ?Exception $previous = null)
+    {
+        parent::__construct($message, $code, $previous);
+        $this->responseBody = $responseBody;
+    }
+
+    /** @return array<string, mixed>|null */
+    public function getResponseBody(): ?array
+    {
+        return $this->responseBody;
+    }
+}
diff --git a/lib/Exception/ClientException.php b/lib/Exception/ClientException.php
new file mode 100644
index 0000000..8330d0d
--- /dev/null
+++ b/lib/Exception/ClientException.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Chip\Exception;
+
+class ClientException extends ChipApiException
+{
+}
diff --git a/lib/Exception/NotFoundException.php b/lib/Exception/NotFoundException.php
new file mode 100644
index 0000000..fd1410b
--- /dev/null
+++ b/lib/Exception/NotFoundException.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Chip\Exception;
+
+class NotFoundException extends ChipApiException
+{
+}
diff --git a/lib/Exception/ServerException.php b/lib/Exception/ServerException.php
new file mode 100644
index 0000000..fe1bd8b
--- /dev/null
+++ b/lib/Exception/ServerException.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Chip\Exception;
+
+class ServerException extends ChipApiException
+{
+}
diff --git a/lib/Exception/ValidationException.php b/lib/Exception/ValidationException.php
new file mode 100644
index 0000000..e0ab291
--- /dev/null
+++ b/lib/Exception/ValidationException.php
@@ -0,0 +1,27 @@
+<?php
+
+namespace Chip\Exception;
+
+class ValidationException extends ChipApiException
+{
+    /** @var array<string, mixed> */
+    protected array $errors = [];
+
+    /**
+     * @param array<string, mixed>|null $responseBody
+     */
+    public function __construct(string $message = '', int $code = 0, ?array $responseBody = null, ?\Exception $previous = null)
+    {
+        parent::__construct($message, $code, $responseBody, $previous);
+
+        if ($responseBody !== null && isset($responseBody['errors']) && is_array($responseBody['errors'])) {
+            $this->errors = $responseBody['errors'];
+        }
+    }
+
+    /** @return array<string, mixed> */
+    public function getErrors(): array
+    {
+        return $this->errors;
+    }
+}
diff --git a/lib/Http/ClientInterface.php b/lib/Http/ClientInterface.php
new file mode 100644
index 0000000..180be9f
--- /dev/null
+++ b/lib/Http/ClientInterface.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Http;
+
+interface ClientInterface
+{
+    /**
+     * @param array<string, mixed> $options
+     * @return \stdClass|array<string, mixed>
+     * @throws \Chip\Exception\ChipApiException
+     */
+    public function request(string $method, string $endpoint, array $options = []): \stdClass|array;
+}
diff --git a/lib/Http/GuzzleClient.php b/lib/Http/GuzzleClient.php
new file mode 100644
index 0000000..c2db5d6
--- /dev/null
+++ b/lib/Http/GuzzleClient.php
@@ -0,0 +1,98 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Http;
+
+use Chip\Exception\AuthenticationException;
+use Chip\Exception\ClientException;
+use Chip\Exception\NotFoundException;
+use Chip\Exception\ServerException;
+use Chip\Exception\ValidationException;
+use GuzzleHttp\Exception\ClientException as GuzzleClientException;
+use GuzzleHttp\Exception\ServerException as GuzzleServerException;
+use Psr\Log\LoggerInterface;
+use Psr\Log\NullLogger;
+
+final class GuzzleClient implements ClientInterface
+{
+    private \GuzzleHttp\Client $client;
+    private LoggerInterface $logger;
+
+    /**
+     * @param array<string, mixed> $config
+     */
+    public function __construct(
+        private readonly string $apiKey,
+        string $baseUri = 'https://gate.chip-in.asia/api/v1/',
+        array $config = [],
+        ?LoggerInterface $logger = null,
+    ) {
+        $this->logger = $logger ?? new NullLogger();
+
+        $mergedConfig = array_merge([
+            'base_uri' => $baseUri,
+            'timeout' => $config['timeout'] ?? 30,
+        ], $config);
+
+        $this->client = new \GuzzleHttp\Client($mergedConfig);
+    }
+
+    /**
+     * @param array<string, mixed> $options
+     * @return \stdClass|array<string, mixed>
+     */
+    public function request(string $method, string $endpoint, array $options = []): \stdClass|array
+    {
+        $headers = [];
+        if ($this->apiKey) {
+            $headers['Authorization'] = 'Bearer ' . $this->apiKey;
+        }
+
+        $mergedOptions = array_merge([
+            'headers' => $headers,
+        ], $options);
+
+        $this->logger->debug('CHIP API request', [
+            'method' => $method,
+            'endpoint' => $endpoint,
+        ]);
+
+        try {
+            $response = $this->client->request($method, $endpoint, $mergedOptions);
+        } catch (GuzzleClientException $e) {
+            $response = $e->getResponse();
+            $statusCode = $response->getStatusCode();
+            $body = json_decode((string) $response->getBody(), true) ?? [];
+            $message = $body['detail'] ?? $body['message'] ?? $e->getMessage();
+
+            $this->logger->error('CHIP API client error', [
+                'status' => $statusCode,
+                'message' => $message,
+            ]);
+
+            throw match ($statusCode) {
+                401 => new AuthenticationException($message, $statusCode, $body, $e),
+                404 => new NotFoundException($message, $statusCode, $body, $e),
+                422 => new ValidationException($message, $statusCode, $body, $e),
+                default => new ClientException($message, $statusCode, $body, $e),
+            };
+        } catch (GuzzleServerException $e) {
+            $response = $e->getResponse();
+            $statusCode = $response->getStatusCode();
+            $body = json_decode((string) $response->getBody(), true) ?? [];
+            $message = $body['detail'] ?? $body['message'] ?? $e->getMessage();
+
+            $this->logger->error('CHIP API server error', [
+                'status' => $statusCode,
+                'message' => $message,
+            ]);
+
+            throw new ServerException($message, $statusCode, $body, $e);
+        }
+
+        $body = (string) $response->getBody()->getContents();
+
+        return json_decode($body, true) ?? new \stdClass();
+    }
+}
diff --git a/lib/Http/RetryClient.php b/lib/Http/RetryClient.php
new file mode 100644
index 0000000..5b17440
--- /dev/null
+++ b/lib/Http/RetryClient.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Http;
+
+use Chip\Exception\ChipApiException;
+use Psr\Log\LoggerInterface;
+use Psr\Log\NullLogger;
+
+final class RetryClient implements ClientInterface
+{
+    private LoggerInterface $logger;
+
+    public function __construct(
+        private readonly ClientInterface $client,
+        private readonly int $maxRetries = 3,
+        private readonly float $baseDelay = 1.0,
+        ?LoggerInterface $logger = null,
+    ) {
+        $this->logger = $logger ?? new NullLogger();
+    }
+
+    /**
+     * @param array<string, mixed> $options
+     * @return \stdClass|array<string, mixed>
+     */
+    public function request(string $method, string $endpoint, array $options = []): \stdClass|array
+    {
+        $attempt = 0;
+
+        while (true) {
+            try {
+                return $this->client->request($method, $endpoint, $options);
+            } catch (ChipApiException $e) {
+                $statusCode = $e->getCode();
+
+                if (! $this->shouldRetry($statusCode, $attempt)) {
+                    throw $e;
+                }
+
+                $delay = $this->calculateDelay($e, $attempt);
+                $attempt++;
+
+                $this->logger->warning('CHIP API retry', [
+                    'attempt' => $attempt,
+                    'delay' => $delay,
+                    'status' => $statusCode,
+                    'endpoint' => $endpoint,
+                ]);
+
+                usleep((int) ($delay * 1_000_000));
+            }
+        }
+    }
+
+    private function shouldRetry(int $statusCode, int $attempt): bool
+    {
+        if ($attempt >= $this->maxRetries) {
+            return false;
+        }
+
+        return $statusCode >= 500 || $statusCode === 429;
+    }
+
+    private function calculateDelay(ChipApiException $e, int $attempt): float
+    {
+        if ($e->getCode() === 429) {
+            $body = $e->getResponseBody() ?? [];
+            $retryAfter = $body['retry_after'] ?? null;
+
+            if (is_numeric($retryAfter)) {
+                return (float) $retryAfter;
+            }
+        }
+
+        return $this->baseDelay * (2 ** $attempt);
+    }
+}
diff --git a/lib/Model/BankAccount.php b/lib/Model/BankAccount.php
index 06cbaf2..3e20854 100644
--- a/lib/Model/BankAccount.php
+++ b/lib/Model/BankAccount.php
@@ -1,21 +1,36 @@
 <?php
+
 namespace Chip\Model;
 
-class BankAccount implements \JsonSerializable {
-	/**
-	 *
-	 * @var string
-	 */
-	public $bank_account;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $bank_code;
-	
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
+class BankAccount implements \JsonSerializable
+{
+    /**
+     *
+     * @var string
+     */
+    public $bank_account;
+
+    /**
+     *
+     * @var string
+     */
+    public $bank_code;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $account = new self();
+        $account->bank_account = $data['bank_account'] ?? '';
+        $account->bank_code = $data['bank_code'] ?? '';
+
+        return $account;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/Billing/BillingTemplate.php b/lib/Model/Billing/BillingTemplate.php
index b5bcde6..40bca58 100644
--- a/lib/Model/Billing/BillingTemplate.php
+++ b/lib/Model/Billing/BillingTemplate.php
@@ -4,50 +4,136 @@
 
 class BillingTemplate implements \JsonSerializable
 {
-  public $type;
-  public $id;
-  public $created_on;
-  public $updated_on;
-
-  public $clients; //required
-  public $purchase; //required
-  public $company_id;
-  public $number_of_billing_cycles;
-  public $is_test;
-  public $user_id;
-  public $brand_id; //required
-  public $title; //required
-  public $is_subscription; //required
-
-  //invoice_* required if `is_subscription` is false
-  public $invoice_issued;
-  public $invoice_due;
-  public $invoice_skip_capture;
-  public $invoice_send_receipt;
-
-  //subscription_* required if `is_subscription` is true
-  public $subscription_period;
-  public $subscription_period_units;
-  public $subscription_due_period;
-  public $subscription_due_period_units;
-  public $subscription_charge_period_end;
-  public $subscription_trial_periods;
-  public $subscription_active;
-  public $subscription_has_active_clients;
-
-  public $force_recurring;
-
-  #[\ReturnTypeWillChange]
-  public function jsonSerialize()
-  {
-    return array_filter((array) $this, array($this, 'allow_non_null'));
-  }
-
-  private function allow_non_null($var)
-  {
-    if (is_null($var)) {
-      return false;
+    /** @var string|null */
+    public $type;
+
+    /** @var string|null */
+    public $id;
+
+    /** @var int|null */
+    public $created_on;
+
+    /** @var int|null */
+    public $updated_on;
+
+    /** @var mixed|null */
+    public $clients;
+
+    /** @var mixed|null */
+    public $purchase;
+
+    /** @var string|null */
+    public $company_id;
+
+    /** @var int|null */
+    public $number_of_billing_cycles;
+
+    /** @var bool|null */
+    public $is_test;
+
+    /** @var string|null */
+    public $user_id;
+
+    /** @var string|null */
+    public $brand_id;
+
+    /** @var string|null */
+    public $title;
+
+    /** @var bool|null */
+    public $is_subscription;
+
+    /** @var int|null */
+    public $invoice_issued;
+
+    /** @var int|null */
+    public $invoice_due;
+
+    /** @var bool|null */
+    public $invoice_skip_capture;
+
+    /** @var bool|null */
+    public $invoice_send_receipt;
+
+    /** @var int|null */
+    public $subscription_period;
+
+    /** @var string|null */
+    public $subscription_period_units;
+
+    /** @var int|null */
+    public $subscription_due_period;
+
+    /** @var string|null */
+    public $subscription_due_period_units;
+
+    /** @var int|null */
+    public $subscription_charge_period_end;
+
+    /** @var int|null */
+    public $subscription_trial_periods;
+
+    /** @var bool|null */
+    public $subscription_active;
+
+    /** @var bool|null */
+    public $subscription_has_active_clients;
+
+    /** @var bool|null */
+    public $force_recurring;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $template = new self();
+        $template->type = $data['type'] ?? null;
+        $template->id = $data['id'] ?? null;
+        $template->created_on = $data['created_on'] ?? null;
+        $template->updated_on = $data['updated_on'] ?? null;
+        $template->clients = $data['clients'] ?? null;
+        $template->purchase = $data['purchase'] ?? null;
+        $template->company_id = $data['company_id'] ?? null;
+        $template->number_of_billing_cycles = $data['number_of_billing_cycles'] ?? null;
+        $template->is_test = $data['is_test'] ?? null;
+        $template->user_id = $data['user_id'] ?? null;
+        $template->brand_id = $data['brand_id'] ?? null;
+        $template->title = $data['title'] ?? null;
+        $template->is_subscription = $data['is_subscription'] ?? null;
+        $template->invoice_issued = $data['invoice_issued'] ?? null;
+        $template->invoice_due = $data['invoice_due'] ?? null;
+        $template->invoice_skip_capture = $data['invoice_skip_capture'] ?? null;
+        $template->invoice_send_receipt = $data['invoice_send_receipt'] ?? null;
+        $template->subscription_period = $data['subscription_period'] ?? null;
+        $template->subscription_period_units = $data['subscription_period_units'] ?? null;
+        $template->subscription_due_period = $data['subscription_due_period'] ?? null;
+        $template->subscription_due_period_units = $data['subscription_due_period_units'] ?? null;
+        $template->subscription_charge_period_end = $data['subscription_charge_period_end'] ?? null;
+        $template->subscription_trial_periods = $data['subscription_trial_periods'] ?? null;
+        $template->subscription_active = $data['subscription_active'] ?? null;
+        $template->subscription_has_active_clients = $data['subscription_has_active_clients'] ?? null;
+        $template->force_recurring = $data['force_recurring'] ?? null;
+
+        return $template;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this, [$this, 'allow_non_null']);
+    }
+
+    /**
+     * @param mixed $var
+     * @return bool
+     */
+    private function allow_non_null($var)
+    {
+        if (is_null($var)) {
+            return false;
+        }
+
+        return true;
     }
-    return true;
-  }
 }
diff --git a/lib/Model/Billing/BillingTemplateClient.php b/lib/Model/Billing/BillingTemplateClient.php
index c45bd4f..301aa9d 100644
--- a/lib/Model/Billing/BillingTemplateClient.php
+++ b/lib/Model/Billing/BillingTemplateClient.php
@@ -4,23 +4,67 @@
 
 class BillingTemplateClient implements \JsonSerializable
 {
-  public $type;
-  public $id;
-  public $created_on;
-  public $updated_on;
-
-  public $client_id; //required
-  public $number_of_billing_cycles_passed;
-  public $status;
-  public $subscription_billing_scheduled_on;
-  public $payment_method_whitelist;
-  public $send_invoice_on_charge_failure;
-  public $send_invoice_on_add_subscriber;
-  public $send_receipt;
-
-  #[\ReturnTypeWillChange]
-  public function jsonSerialize()
-  {
-    return array_filter((array) $this);
-  }
+    /** @var string|null */
+    public $type;
+
+    /** @var string|null */
+    public $id;
+
+    /** @var int|null */
+    public $created_on;
+
+    /** @var int|null */
+    public $updated_on;
+
+    /** @var string|null */
+    public $client_id;
+
+    /** @var int|null */
+    public $number_of_billing_cycles_passed;
+
+    /** @var string|null */
+    public $status;
+
+    /** @var int|null */
+    public $subscription_billing_scheduled_on;
+
+    /** @var string[]|null */
+    public $payment_method_whitelist;
+
+    /** @var bool|null */
+    public $send_invoice_on_charge_failure;
+
+    /** @var bool|null */
+    public $send_invoice_on_add_subscriber;
+
+    /** @var bool|null */
+    public $send_receipt;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $client = new self();
+        $client->type = $data['type'] ?? null;
+        $client->id = $data['id'] ?? null;
+        $client->created_on = $data['created_on'] ?? null;
+        $client->updated_on = $data['updated_on'] ?? null;
+        $client->client_id = $data['client_id'] ?? null;
+        $client->number_of_billing_cycles_passed = $data['number_of_billing_cycles_passed'] ?? null;
+        $client->status = $data['status'] ?? null;
+        $client->subscription_billing_scheduled_on = $data['subscription_billing_scheduled_on'] ?? null;
+        $client->payment_method_whitelist = $data['payment_method_whitelist'] ?? null;
+        $client->send_invoice_on_charge_failure = $data['send_invoice_on_charge_failure'] ?? null;
+        $client->send_invoice_on_add_subscriber = $data['send_invoice_on_add_subscriber'] ?? null;
+        $client->send_receipt = $data['send_receipt'] ?? null;
+
+        return $client;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/Billing/BillingTemplateClientAddSubscriber.php b/lib/Model/Billing/BillingTemplateClientAddSubscriber.php
index 5db7fdd..46d731f 100644
--- a/lib/Model/Billing/BillingTemplateClientAddSubscriber.php
+++ b/lib/Model/Billing/BillingTemplateClientAddSubscriber.php
@@ -2,24 +2,35 @@
 
 namespace Chip\Model\Billing;
 
+use Chip\Model\Purchase;
+
 class BillingTemplateClientAddSubscriber implements \JsonSerializable
 {
+    /** @var BillingTemplateClient|null */
+    public $billing_template_client;
+
+    /** @var Purchase|null */
+    public $purchase;
 
-  /**
-  *
-  * @var \Chip\Model\Billing\BillingTemplateClient
-  */
-  public $billing_template_client;
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $result = new self();
+        $result->billing_template_client = isset($data['billing_template_client']) && is_array($data['billing_template_client'])
+            ? BillingTemplateClient::fromArray($data['billing_template_client'])
+            : null;
+        $result->purchase = isset($data['purchase']) && is_array($data['purchase'])
+            ? Purchase::fromArray($data['purchase'])
+            : null;
 
-  /**
-  *
-  * @var \Chip\Model\Purchase
-  */
-  public $purchase;
+        return $result;
+    }
 
-  #[\ReturnTypeWillChange]
-  public function jsonSerialize()
-  {
-    return array_filter((array) $this);
-  }
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/Billing/BillingTemplateClientList.php b/lib/Model/Billing/BillingTemplateClientList.php
index 4c50b00..8da146f 100644
--- a/lib/Model/Billing/BillingTemplateClientList.php
+++ b/lib/Model/Billing/BillingTemplateClientList.php
@@ -4,19 +4,33 @@
 
 class BillingTemplateClientList implements \JsonSerializable
 {
+    /** @var BillingTemplateClient[]|null */
+    public $results;
 
-  /**
-   *
-   * @var BillingTemplateClient[]
-   */
-  public $results;
+    /** @var string|null */
+    public $next;
 
-  public $next;
-  public $previous;
+    /** @var string|null */
+    public $previous;
 
-  #[\ReturnTypeWillChange]
-  public function jsonSerialize()
-  {
-    return array_filter((array) $this);
-  }
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $list = new self();
+        $list->results = isset($data['results']) && is_array($data['results'])
+            ? array_map(fn (array $r) => BillingTemplateClient::fromArray($r), $data['results'])
+            : null;
+        $list->next = $data['next'] ?? null;
+        $list->previous = $data['previous'] ?? null;
+
+        return $list;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/Billing/BillingTemplateList.php b/lib/Model/Billing/BillingTemplateList.php
index 775223e..4369fc1 100644
--- a/lib/Model/Billing/BillingTemplateList.php
+++ b/lib/Model/Billing/BillingTemplateList.php
@@ -4,19 +4,33 @@
 
 class BillingTemplateList implements \JsonSerializable
 {
+    /** @var BillingTemplate[]|null */
+    public $results;
 
-  /**
-   *
-   * @var BillingTemplate[]
-   */
-  public $results;
+    /** @var string|null */
+    public $next;
 
-  public $next;
-  public $previous;
+    /** @var string|null */
+    public $previous;
 
-  #[\ReturnTypeWillChange]
-  public function jsonSerialize()
-  {
-    return array_filter((array) $this);
-  }
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $list = new self();
+        $list->results = isset($data['results']) && is_array($data['results'])
+            ? array_map(fn (array $r) => BillingTemplate::fromArray($r), $data['results'])
+            : null;
+        $list->next = $data['next'] ?? null;
+        $list->previous = $data['previous'] ?? null;
+
+        return $list;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/ClientDetails.php b/lib/Model/ClientDetails.php
index 17c88bc..f229bc5 100644
--- a/lib/Model/ClientDetails.php
+++ b/lib/Model/ClientDetails.php
@@ -1,124 +1,183 @@
 <?php
+
 namespace Chip\Model;
 
-class ClientDetails implements \JsonSerializable {
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $id;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $email;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $phone;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $full_name;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $personal_code;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $street_address;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $country;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $city;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $zip_code;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $shipping_street_address;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $shipping_country;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $shipping_city;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $shipping_zip_code;
-	
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $cc;
-	
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $bcc;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $legal_name;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $brand_name;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $registration_number;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $tax_number;
-	
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
+class ClientDetails implements \JsonSerializable
+{
+    /**
+     *
+     * @var string
+     */
+    public $id;
+
+    /**
+     *
+     * @var string
+     */
+    public $email;
+
+    /**
+     *
+     * @var string
+     */
+    public $phone;
+
+    /**
+     *
+     * @var string
+     */
+    public $full_name;
+
+    /**
+     *
+     * @var string
+     */
+    public $personal_code;
+
+    /**
+     *
+     * @var string
+     */
+    public $street_address;
+
+    /**
+     *
+     * @var string
+     */
+    public $country;
+
+    /**
+     *
+     * @var string
+     */
+    public $city;
+
+    /**
+     *
+     * @var string
+     */
+    public $zip_code;
+
+    /**
+     *
+     * @var string
+     */
+    public $shipping_street_address;
+
+    /**
+     *
+     * @var string
+     */
+    public $shipping_country;
+
+    /**
+     *
+     * @var string
+     */
+    public $shipping_city;
+
+    /**
+     *
+     * @var string
+     */
+    public $shipping_zip_code;
+
+    /**
+     *
+     * @var string[]
+     */
+    public $cc;
+
+    /**
+     *
+     * @var string[]
+     */
+    public $bcc;
+
+    /**
+     *
+     * @var string
+     */
+    public $legal_name;
+
+    /**
+     *
+     * @var string
+     */
+    public $brand_name;
+
+    /**
+     *
+     * @var string
+     */
+    public $registration_number;
+
+    /**
+     *
+     * @var string
+     */
+    public $tax_number;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $state;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $shipping_state;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $bank_account;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $bank_code;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $client = new self();
+        $client->id = $data['id'] ?? '';
+        $client->email = $data['email'] ?? '';
+        $client->phone = $data['phone'] ?? '';
+        $client->full_name = $data['full_name'] ?? '';
+        $client->personal_code = $data['personal_code'] ?? '';
+        $client->street_address = $data['street_address'] ?? '';
+        $client->country = $data['country'] ?? '';
+        $client->city = $data['city'] ?? '';
+        $client->zip_code = $data['zip_code'] ?? '';
+        $client->shipping_street_address = $data['shipping_street_address'] ?? '';
+        $client->shipping_country = $data['shipping_country'] ?? '';
+        $client->shipping_city = $data['shipping_city'] ?? '';
+        $client->shipping_zip_code = $data['shipping_zip_code'] ?? '';
+        $client->cc = $data['cc'] ?? [];
+        $client->bcc = $data['bcc'] ?? [];
+        $client->legal_name = $data['legal_name'] ?? '';
+        $client->brand_name = $data['brand_name'] ?? '';
+        $client->registration_number = $data['registration_number'] ?? '';
+        $client->tax_number = $data['tax_number'] ?? '';
+        $client->state = $data['state'] ?? null;
+        $client->shipping_state = $data['shipping_state'] ?? null;
+        $client->bank_account = $data['bank_account'] ?? null;
+        $client->bank_code = $data['bank_code'] ?? null;
+
+        return $client;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/ClientList.php b/lib/Model/ClientList.php
index d35a9b2..b7c5e98 100644
--- a/lib/Model/ClientList.php
+++ b/lib/Model/ClientList.php
@@ -4,19 +4,34 @@
 
 class ClientList implements \JsonSerializable
 {
+    /** @var ClientDetails[]|null */
+    public $results;
 
-  /**
-   *
-   * @var ClientDetails[]
-   */
-  public $results;
+    /** @var string|null */
+    public $next;
 
-  public $next;
-  public $previous;
+    /** @var string|null */
+    public $previous;
 
-  #[\ReturnTypeWillChange]
-  public function jsonSerialize()
-  {
-    return array_filter((array) $this);
-  }
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $list = new self();
+        $list->results = array_map(
+            fn (array $c) => ClientDetails::fromArray($c),
+            $data['results'] ?? []
+        );
+        $list->next = $data['next'] ?? null;
+        $list->previous = $data['previous'] ?? null;
+
+        return $list;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/ClientRecurringToken.php b/lib/Model/ClientRecurringToken.php
new file mode 100644
index 0000000..4998b48
--- /dev/null
+++ b/lib/Model/ClientRecurringToken.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace Chip\Model;
+
+class ClientRecurringToken implements \JsonSerializable
+{
+    /** @var string|null */
+    public $type;
+
+    /** @var string|null */
+    public $id;
+
+    /** @var int|null */
+    public $created_on;
+
+    /** @var int|null */
+    public $updated_on;
+
+    /** @var string|null */
+    public $payment_method;
+
+    /** @var string|null */
+    public $description;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $token = new self();
+        $token->type = $data['type'] ?? null;
+        $token->id = $data['id'] ?? null;
+        $token->created_on = $data['created_on'] ?? null;
+        $token->updated_on = $data['updated_on'] ?? null;
+        $token->payment_method = $data['payment_method'] ?? null;
+        $token->description = $data['description'] ?? null;
+
+        return $token;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/ClientRecurringTokenList.php b/lib/Model/ClientRecurringTokenList.php
new file mode 100644
index 0000000..d79d784
--- /dev/null
+++ b/lib/Model/ClientRecurringTokenList.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace Chip\Model;
+
+class ClientRecurringTokenList implements \JsonSerializable
+{
+    /** @var ClientRecurringToken[]|null */
+    public $results;
+
+    /** @var string|null */
+    public $next;
+
+    /** @var string|null */
+    public $previous;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $list = new self();
+        $list->results = array_map(
+            fn (array $t) => ClientRecurringToken::fromArray($t),
+            $data['results'] ?? []
+        );
+        $list->next = $data['next'] ?? null;
+        $list->previous = $data['previous'] ?? null;
+
+        return $list;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/CompanyStatement.php b/lib/Model/CompanyStatement.php
new file mode 100644
index 0000000..51d75a5
--- /dev/null
+++ b/lib/Model/CompanyStatement.php
@@ -0,0 +1,74 @@
+<?php
+
+namespace Chip\Model;
+
+class CompanyStatement implements \JsonSerializable
+{
+    /** @var string|null */
+    public $type;
+
+    /** @var string|null */
+    public $id;
+
+    /** @var int|null */
+    public $created_on;
+
+    /** @var int|null */
+    public $updated_on;
+
+    /** @var string|null */
+    public $format;
+
+    /** @var string|null */
+    public $timezone;
+
+    /** @var bool|null */
+    public $is_test;
+
+    /** @var string|null */
+    public $company_uid;
+
+    /** @var string|null */
+    public $query_string;
+
+    /** @var string|null */
+    public $status;
+
+    /** @var string|null */
+    public $download_url;
+
+    /** @var int|null */
+    public $began_on;
+
+    /** @var int|null */
+    public $finished_on;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $statement = new self();
+        $statement->type = $data['type'] ?? null;
+        $statement->id = $data['id'] ?? null;
+        $statement->created_on = $data['created_on'] ?? null;
+        $statement->updated_on = $data['updated_on'] ?? null;
+        $statement->format = $data['format'] ?? null;
+        $statement->timezone = $data['timezone'] ?? null;
+        $statement->is_test = $data['is_test'] ?? null;
+        $statement->company_uid = $data['company_uid'] ?? null;
+        $statement->query_string = $data['query_string'] ?? null;
+        $statement->status = $data['status'] ?? null;
+        $statement->download_url = $data['download_url'] ?? null;
+        $statement->began_on = $data['began_on'] ?? null;
+        $statement->finished_on = $data['finished_on'] ?? null;
+
+        return $statement;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/CompanyStatementList.php b/lib/Model/CompanyStatementList.php
new file mode 100644
index 0000000..30dc2a1
--- /dev/null
+++ b/lib/Model/CompanyStatementList.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace Chip\Model;
+
+class CompanyStatementList implements \JsonSerializable
+{
+    /** @var CompanyStatement[]|null */
+    public $results;
+
+    /** @var string|null */
+    public $next;
+
+    /** @var string|null */
+    public $previous;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $list = new self();
+        $list->results = array_map(
+            fn (array $s) => CompanyStatement::fromArray($s),
+            $data['results'] ?? []
+        );
+        $list->next = $data['next'] ?? null;
+        $list->previous = $data['previous'] ?? null;
+
+        return $list;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/IssuerDetails.php b/lib/Model/IssuerDetails.php
index bf0ff34..254a190 100644
--- a/lib/Model/IssuerDetails.php
+++ b/lib/Model/IssuerDetails.php
@@ -1,69 +1,95 @@
 <?php
+
 namespace Chip\Model;
 
-class IssuerDetails implements \JsonSerializable {
-	/**
-	 *
-	 * @var string
-	 */
-	public $website;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $legal_street_address;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $legal_country;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $legal_city;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $legal_zip_code;
-	
-	/**
-	 *
-	 * @var BankAccount[]
-	 */
-	public $bank_accounts;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $legal_name;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $brand_name;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $registration_number;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $tax_number;
-	
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
+class IssuerDetails implements \JsonSerializable
+{
+    /**
+     *
+     * @var string
+     */
+    public $website;
+
+    /**
+     *
+     * @var string
+     */
+    public $legal_street_address;
+
+    /**
+     *
+     * @var string
+     */
+    public $legal_country;
+
+    /**
+     *
+     * @var string
+     */
+    public $legal_city;
+
+    /**
+     *
+     * @var string
+     */
+    public $legal_zip_code;
+
+    /**
+     *
+     * @var BankAccount[]
+     */
+    public $bank_accounts;
+
+    /**
+     *
+     * @var string
+     */
+    public $legal_name;
+
+    /**
+     *
+     * @var string
+     */
+    public $brand_name;
+
+    /**
+     *
+     * @var string
+     */
+    public $registration_number;
+
+    /**
+     *
+     * @var string
+     */
+    public $tax_number;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $details = new self();
+        $details->website = $data['website'] ?? '';
+        $details->legal_street_address = $data['legal_street_address'] ?? '';
+        $details->legal_country = $data['legal_country'] ?? '';
+        $details->legal_city = $data['legal_city'] ?? '';
+        $details->legal_zip_code = $data['legal_zip_code'] ?? '';
+        $details->bank_accounts = array_map(
+            fn (array $a) => BankAccount::fromArray($a),
+            $data['bank_accounts'] ?? []
+        );
+        $details->legal_name = $data['legal_name'] ?? '';
+        $details->brand_name = $data['brand_name'] ?? '';
+        $details->registration_number = $data['registration_number'] ?? '';
+        $details->tax_number = $data['tax_number'] ?? '';
+
+        return $details;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/PaymentDetails.php b/lib/Model/PaymentDetails.php
index 6414443..6ed79fa 100644
--- a/lib/Model/PaymentDetails.php
+++ b/lib/Model/PaymentDetails.php
@@ -1,75 +1,99 @@
 <?php
+
 namespace Chip\Model;
 
-class PaymentDetails implements \JsonSerializable {
-	/**
-	 *
-	 * @var bool
-	 */
-	public $is_outgoing;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $payment_type;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $amount;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $currency;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $net_amount;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $fee_amount;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $pending_amount;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $pending_unfreeze_on;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $description;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $paid_on;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $remote_paid_on;
-	
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
+class PaymentDetails implements \JsonSerializable
+{
+    /**
+     *
+     * @var bool
+     */
+    public $is_outgoing;
+
+    /**
+     *
+     * @var string
+     */
+    public $payment_type;
+
+    /**
+     *
+     * @var int
+     */
+    public $amount;
+
+    /**
+     *
+     * @var string
+     */
+    public $currency;
+
+    /**
+     *
+     * @var int
+     */
+    public $net_amount;
+
+    /**
+     *
+     * @var int
+     */
+    public $fee_amount;
+
+    /**
+     *
+     * @var int
+     */
+    public $pending_amount;
+
+    /**
+     *
+     * @var int
+     */
+    public $pending_unfreeze_on;
+
+    /**
+     *
+     * @var string
+     */
+    public $description;
+
+    /**
+     *
+     * @var int
+     */
+    public $paid_on;
+
+    /**
+     *
+     * @var int
+     */
+    public $remote_paid_on;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $details = new self();
+        $details->is_outgoing = $data['is_outgoing'] ?? false;
+        $details->payment_type = $data['payment_type'] ?? '';
+        $details->amount = $data['amount'] ?? 0;
+        $details->currency = $data['currency'] ?? '';
+        $details->net_amount = $data['net_amount'] ?? 0;
+        $details->fee_amount = $data['fee_amount'] ?? 0;
+        $details->pending_amount = $data['pending_amount'] ?? 0;
+        $details->pending_unfreeze_on = $data['pending_unfreeze_on'] ?? 0;
+        $details->description = $data['description'] ?? '';
+        $details->paid_on = $data['paid_on'] ?? 0;
+        $details->remote_paid_on = $data['remote_paid_on'] ?? 0;
+
+        return $details;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
diff --git a/lib/Model/PaymentMethods.php b/lib/Model/PaymentMethods.php
index 4a69f76..93ee1f3 100644
--- a/lib/Model/PaymentMethods.php
+++ b/lib/Model/PaymentMethods.php
@@ -1,46 +1,68 @@
 <?php
+
 namespace Chip\Model;
 
-class PaymentMethods implements \JsonSerializable {
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $available_payment_methods;
-	
-	/**
-	 *
-	 * @var string[][]
-	 */
-	public $by_country;
-	
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $country_names;
-	
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $names;
-	
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $card_methods;
-
-	/**
-	 *
-	 * @var array
-	 */
-	public $logos;
-	
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
-}
+class PaymentMethods implements \JsonSerializable
+{
+    /**
+     *
+     * @var string[]
+     */
+    public $available_payment_methods;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<string, string[]>
+     */
+    public $by_country;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<string, string>
+     */
+    public $country_names;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<string, string>
+     */
+    public $names;
 
+    /**
+     *
+     * @var string[]
+     */
+    public $card_methods;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<string, string|string[]>
+     */
+    public $logos;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $methods = new self();
+        $methods->available_payment_methods = $data['available_payment_methods'] ?? [];
+        $methods->by_country = $data['by_country'] ?? [];
+        $methods->country_names = $data['country_names'] ?? [];
+        $methods->names = $data['names'] ?? [];
+        $methods->card_methods = $data['card_methods'] ?? [];
+        $methods->logos = $data['logos'] ?? [];
+
+        return $methods;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/Product.php b/lib/Model/Product.php
index 426d001..9e771e8 100644
--- a/lib/Model/Product.php
+++ b/lib/Model/Product.php
@@ -1,42 +1,77 @@
 <?php
+
 namespace Chip\Model;
 
-class Product implements \JsonSerializable {
-	
-	/**
-	 * @var string
-	 */
-	public $name;
-	
-	/**
-	 * @var float
-	 */
-	public $quantity;
-	
-	/**
-	 * @var int
-	 */
-	public $price;
-	
-	/**
-	 * @var int
-	 */
-	public $discount;
-	
-	/**
-	 * @var float
-	 */
-	public $tax_percent;
-	
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this, array($this, 'allow_non_null'));
-	}
-
-	private function allow_non_null($var) {
-		if (is_null($var)){
-			return false;
-		}
-		return true;
-	}
-}
\ No newline at end of file
+class Product implements \JsonSerializable
+{
+    /**
+     * @var string|null
+     */
+    public $name;
+
+    /**
+     * @var string|null
+     */
+    public $quantity;
+
+    /**
+     * @var int|null
+     */
+    public $price;
+
+    /**
+     * @var int|null
+     */
+    public $discount;
+
+    /**
+     * @var string|null
+     */
+    public $tax_percent;
+
+    /**
+     * @var string|null
+     */
+    public $category;
+
+    /**
+     * @var int|null
+     */
+    public $total_price_override;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $product = new self();
+        $product->name = $data['name'] ?? null;
+        $product->quantity = $data['quantity'] ?? null;
+        $product->price = $data['price'] ?? null;
+        $product->discount = $data['discount'] ?? null;
+        $product->tax_percent = $data['tax_percent'] ?? null;
+        $product->category = $data['category'] ?? null;
+        $product->total_price_override = $data['total_price_override'] ?? null;
+
+        return $product;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this, [$this, 'allow_non_null']);
+    }
+
+    /**
+     * @param mixed $var
+     * @return bool
+     */
+    private function allow_non_null($var)
+    {
+        if (is_null($var)) {
+            return false;
+        }
+
+        return true;
+    }
+}
diff --git a/lib/Model/Purchase.php b/lib/Model/Purchase.php
index 939bf79..07d7f5a 100644
--- a/lib/Model/Purchase.php
+++ b/lib/Model/Purchase.php
@@ -1,246 +1,404 @@
 <?php
-namespace Chip\Model;
 
-class Purchase implements \JsonSerializable {
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $id;
-
-	/**
-	 *
-	 * @var ClientDetails
-	 */
-	public $client;
-
-	/**
-	 *
-	 * @var PurchaseDetails
-	 */
-	public $purchase;
-
-	/**
-	 *
-	 * @var PaymentDetails
-	 */
-	public $payment;
-
-	/**
-	 *
-	 * @var IssuerDetails
-	 */
-	public $issuer_details;
-
-	/**
-	 *
-	 * @var object
-	 */
-	public $transaction_data;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $status;
-
-	/**
-	 *
-	 * @var object
-	 */
-	public $status_history;
-
-	/**
-	 *
-	 * @var int
-	 */
-	public $viewed_on;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $company_id;
-
-	/**
-	 *
-	 * @var bool
-	 */
-	public $is_test;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $user_id;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $brand_id;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $billing_template_id;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $client_id;
-
-	/**
-	 *
-	 * @var bool
-	 */
-	public $send_receipt;
-
-	/**
-	 *
-	 * @var bool
-	 */
-	public $is_recurring_token;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $recurring_token;
-
-	/**
-	 *
-	 * @var bool
-	 */
-	public $force_recurring;
-
-	/**
-	 *
-	 * @var bool
-	 */
-	public $skip_capture;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $reference_generated;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $reference;
-
-	/**
-	 *
-	 * @var int
-	 */
-	public $issued;
-
-	/**
-	 *
-	 * @var int
-	 */
-	public $due;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $refund_availability;
-
-	/**
-	 *
-	 * @var int
-	 */
-	public $refundable_amount;
-
-	/**
-	 *
-	 * @var object
-	 */
-	public $currency_conversion;
-
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $payment_method_whitelist;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $success_redirect;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $failure_redirect;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $cancel_redirect;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $success_callback;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $creator_agent;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $platform;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $product;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $created_from_ip;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $invoice_url;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $checkout_url;
-
-	/**
-	 *
-	 * @var string
-	 */
-	public $direct_post_url;
-
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
+namespace Chip\Model;
 
+class Purchase implements \JsonSerializable
+{
+    /**
+     *
+     * @var string
+     */
+    public $id;
+
+    /**
+     *
+     * @var ClientDetails
+     */
+    public $client;
+
+    /**
+     *
+     * @var PurchaseDetails
+     */
+    public $purchase;
+
+    /**
+     *
+     * @var PaymentDetails
+     */
+    public $payment;
+
+    /**
+     *
+     * @var IssuerDetails
+     */
+    public $issuer_details;
+
+    /**
+     *
+     * @var object
+     */
+    public $transaction_data;
+
+    /**
+     *
+     * @var string
+     */
+    public $status;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<int, \stdClass>
+     */
+    public $status_history;
+
+    /**
+     *
+     * @var int
+     */
+    public $viewed_on;
+
+    /**
+     *
+     * @var string
+     */
+    public $company_id;
+
+    /**
+     *
+     * @var bool
+     */
+    public $is_test;
+
+    /**
+     *
+     * @var string
+     */
+    public $user_id;
+
+    /**
+     *
+     * @var string
+     */
+    public $brand_id;
+
+    /**
+     *
+     * @var string
+     */
+    public $billing_template_id;
+
+    /**
+     *
+     * @var string
+     */
+    public $client_id;
+
+    /**
+     *
+     * @var bool
+     */
+    public $send_receipt;
+
+    /**
+     *
+     * @var bool
+     */
+    public $is_recurring_token;
+
+    /**
+     *
+     * @var string
+     */
+    public $recurring_token;
+
+    /**
+     *
+     * @var bool
+     */
+    public $force_recurring;
+
+    /**
+     *
+     * @var bool
+     */
+    public $skip_capture;
+
+    /**
+     *
+     * @var string
+     */
+    public $reference_generated;
+
+    /**
+     *
+     * @var string
+     */
+    public $reference;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $issued;
+
+    /**
+     *
+     * @var int
+     */
+    public $due;
+
+    /**
+     *
+     * @var string
+     */
+    public $refund_availability;
+
+    /**
+     *
+     * @var int
+     */
+    public $refundable_amount;
+
+    /**
+     *
+     * @var object
+     */
+    public $currency_conversion;
+
+    /**
+     *
+     * @var string[]
+     */
+    public $payment_method_whitelist;
+
+    /**
+     *
+     * @var string
+     */
+    public $success_redirect;
+
+    /**
+     *
+     * @var string
+     */
+    public $failure_redirect;
+
+    /**
+     *
+     * @var string
+     */
+    public $cancel_redirect;
+
+    /**
+     *
+     * @var string
+     */
+    public $success_callback;
+
+    /**
+     *
+     * @var string
+     */
+    public $creator_agent;
+
+    /**
+     *
+     * @var string
+     */
+    public $platform;
+
+    /**
+     *
+     * @var string
+     */
+    public $product;
+
+    /**
+     *
+     * @var string
+     */
+    public $created_from_ip;
+
+    /**
+     *
+     * @var string
+     */
+    public $invoice_url;
+
+    /**
+     *
+     * @var string
+     */
+    public $checkout_url;
+
+    /**
+     *
+     * @var string
+     */
+    public $direct_post_url;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $notes;
+
+    /**
+     *
+     * @var bool
+     */
+    public $marked_as_paid;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $order_id;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<int, mixed>
+     */
+    public $upsell_campaigns;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $referral_campaign_id;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $referral_code;
+
+    /**
+     *
+     * @var object|null
+     */
+    public $referral_code_details;
+
+    /**
+     *
+     * @var string|null
+     */
+    public $referral_code_generated;
+
+    /**
+     *
+     * @var object|null
+     */
+    public $retain_level_details;
+
+    /**
+     *
+     * @var bool
+     */
+    public $can_retrieve;
+
+    /**
+     *
+     * @var bool
+     */
+    public $can_chargeback;
+
+    /**
+     *
+     * @var bool
+     */
+    public $can_reverse_chargeback;
+
+    /**
+     *
+     * @var string[]
+     */
+    public $tags;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $purchase = new self();
+        $purchase->id = $data['id'] ?? '';
+
+        if (isset($data['client']) && is_array($data['client'])) {
+            $purchase->client = ClientDetails::fromArray($data['client']);
+        }
+
+        if (isset($data['purchase']) && is_array($data['purchase'])) {
+            $purchase->purchase = PurchaseDetails::fromArray($data['purchase']);
+        }
+
+        if (isset($data['payment']) && is_array($data['payment'])) {
+            $purchase->payment = PaymentDetails::fromArray($data['payment']);
+        }
+
+        if (isset($data['issuer_details']) && is_array($data['issuer_details'])) {
+            $purchase->issuer_details = IssuerDetails::fromArray($data['issuer_details']);
+        }
+
+        $purchase->transaction_data = isset($data['transaction_data']) ? (object) $data['transaction_data'] : new \stdClass();
+        $purchase->status = $data['status'] ?? '';
+        $purchase->status_history = array_map(
+            fn (array $h) => (object) $h,
+            $data['status_history'] ?? []
+        );
+        $purchase->viewed_on = $data['viewed_on'] ?? 0;
+        $purchase->company_id = $data['company_id'] ?? '';
+        $purchase->is_test = $data['is_test'] ?? false;
+        $purchase->user_id = $data['user_id'] ?? '';
+        $purchase->brand_id = $data['brand_id'] ?? '';
+        $purchase->billing_template_id = $data['billing_template_id'] ?? '';
+        $purchase->client_id = $data['client_id'] ?? '';
+        $purchase->send_receipt = $data['send_receipt'] ?? false;
+        $purchase->is_recurring_token = $data['is_recurring_token'] ?? false;
+        $purchase->recurring_token = $data['recurring_token'] ?? '';
+        $purchase->force_recurring = $data['force_recurring'] ?? false;
+        $purchase->skip_capture = $data['skip_capture'] ?? false;
+        $purchase->reference_generated = $data['reference_generated'] ?? '';
+        $purchase->reference = $data['reference'] ?? '';
+        $purchase->issued = $data['issued'] ?? null;
+        $purchase->due = $data['due'] ?? 0;
+        $purchase->refund_availability = $data['refund_availability'] ?? '';
+        $purchase->refundable_amount = $data['refundable_amount'] ?? 0;
+        $purchase->currency_conversion = isset($data['currency_conversion']) ? (object) $data['currency_conversion'] : new \stdClass();
+        $purchase->payment_method_whitelist = $data['payment_method_whitelist'] ?? [];
+        $purchase->success_redirect = $data['success_redirect'] ?? '';
+        $purchase->failure_redirect = $data['failure_redirect'] ?? '';
+        $purchase->cancel_redirect = $data['cancel_redirect'] ?? '';
+        $purchase->success_callback = $data['success_callback'] ?? '';
+        $purchase->creator_agent = $data['creator_agent'] ?? '';
+        $purchase->platform = $data['platform'] ?? '';
+        $purchase->product = $data['product'] ?? '';
+        $purchase->created_from_ip = $data['created_from_ip'] ?? '';
+        $purchase->invoice_url = $data['invoice_url'] ?? '';
+        $purchase->checkout_url = $data['checkout_url'] ?? '';
+        $purchase->direct_post_url = $data['direct_post_url'] ?? '';
+        $purchase->notes = $data['notes'] ?? null;
+        $purchase->marked_as_paid = $data['marked_as_paid'] ?? false;
+        $purchase->order_id = $data['order_id'] ?? null;
+        $purchase->upsell_campaigns = $data['upsell_campaigns'] ?? [];
+        $purchase->referral_campaign_id = $data['referral_campaign_id'] ?? null;
+        $purchase->referral_code = $data['referral_code'] ?? null;
+        $purchase->referral_code_details = isset($data['referral_code_details']) ? (object) $data['referral_code_details'] : null;
+        $purchase->referral_code_generated = $data['referral_code_generated'] ?? null;
+        $purchase->retain_level_details = isset($data['retain_level_details']) ? (object) $data['retain_level_details'] : null;
+        $purchase->can_retrieve = $data['can_retrieve'] ?? false;
+        $purchase->can_chargeback = $data['can_chargeback'] ?? false;
+        $purchase->can_reverse_chargeback = $data['can_reverse_chargeback'] ?? false;
+        $purchase->tags = $data['tags'] ?? [];
+
+        return $purchase;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
 }
-
diff --git a/lib/Model/PurchaseDetails.php b/lib/Model/PurchaseDetails.php
index d495dd6..1e624ba 100644
--- a/lib/Model/PurchaseDetails.php
+++ b/lib/Model/PurchaseDetails.php
@@ -1,95 +1,160 @@
 <?php
+
 namespace Chip\Model;
 
-class PurchaseDetails implements \JsonSerializable {
-	/**
-	 *
-	 * @var string
-	 */
-	public $currency;
-	
-	/**
-	 *
-	 * @var Product[]
-	 */
-	public $products;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $total;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $language;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $notes;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $debt;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $subtotal_override;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $total_tax_override;
-	
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $total_discount_override;
-	
-	/**
-	 *
-	 * @var int
-	 */
-	public $total_override;
-	
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $request_client_details;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $timezone;
-	
-	/**
-	 *
-	 * @var bool
-	 */
-	public $due_strict;
-	
-	/**
-	 *
-	 * @var string
-	 */
-	public $email_message;
-
-  #[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
-}
+class PurchaseDetails implements \JsonSerializable
+{
+    /**
+     *
+     * @var string
+     */
+    public $currency;
+
+    /**
+     *
+     * @var Product[]
+     */
+    public $products;
+
+    /**
+     *
+     * @var int
+     */
+    public $total;
+
+    /**
+     *
+     * @var string
+     */
+    public $language;
+
+    /**
+     *
+     * @var string
+     */
+    public $notes;
+
+    /**
+     *
+     * @var int
+     */
+    public $debt;
+
+    /**
+     *
+     * @var int
+     */
+    public $subtotal_override;
+
+    /**
+     *
+     * @var int
+     */
+    public $total_tax_override;
+
+
+    /**
+     *
+     * @var int
+     */
+    public $total_discount_override;
+
+    /**
+     *
+     * @var int
+     */
+    public $total_override;
 
+    /**
+     *
+     * @var string[]
+     */
+    public $request_client_details;
+
+    /**
+     *
+     * @var string
+     */
+    public $timezone;
+
+    /**
+     *
+     * @var bool
+     */
+    public $due_strict;
+
+    /**
+     *
+     * @var string
+     */
+    public $email_message;
+
+    /**
+     *
+     * @var array
+     * @phpstan-var array<int, mixed>
+     */
+    public $shipping_options;
+
+    /**
+     *
+     * @var object|null
+     */
+    public $payment_method_details;
+
+    /**
+     *
+     * @var bool
+     */
+    public $has_upsell_products;
+
+    /**
+     *
+     * @var bool
+     */
+    public $single_attempt;
+
+    /**
+     *
+     * @var object|null
+     */
+    public $metadata;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $details = new self();
+        $details->currency = $data['currency'] ?? '';
+        $details->products = array_map(
+            fn (array $p) => Product::fromArray($p),
+            $data['products'] ?? []
+        );
+        $details->total = $data['total'] ?? 0;
+        $details->language = $data['language'] ?? '';
+        $details->notes = $data['notes'] ?? '';
+        $details->debt = $data['debt'] ?? 0;
+        $details->subtotal_override = $data['subtotal_override'] ?? 0;
+        $details->total_tax_override = $data['total_tax_override'] ?? 0;
+        $details->total_discount_override = $data['total_discount_override'] ?? 0;
+        $details->total_override = $data['total_override'] ?? 0;
+        $details->request_client_details = $data['request_client_details'] ?? [];
+        $details->timezone = $data['timezone'] ?? '';
+        $details->due_strict = $data['due_strict'] ?? false;
+        $details->email_message = $data['email_message'] ?? '';
+        $details->shipping_options = $data['shipping_options'] ?? [];
+        $details->payment_method_details = isset($data['payment_method_details']) ? (object) $data['payment_method_details'] : null;
+        $details->has_upsell_products = $data['has_upsell_products'] ?? false;
+        $details->single_attempt = $data['single_attempt'] ?? false;
+        $details->metadata = isset($data['metadata']) ? (object) $data['metadata'] : null;
+
+        return $details;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/Webhook.php b/lib/Model/Webhook.php
index e516c11..313c70e 100644
--- a/lib/Model/Webhook.php
+++ b/lib/Model/Webhook.php
@@ -1,65 +1,85 @@
 <?php
+
 namespace Chip\Model;
 
 class Webhook implements \JsonSerializable
 {
-	/**
-	 *
-	 * @var string
-	 */
-	public $type;
+    /**
+     *
+     * @var string
+     */
+    public $type;
 
-	/**
-	 *
-	 * @var string
-	 */
-	public $id;
+    /**
+     *
+     * @var string
+     */
+    public $id;
 
-	/**
-	 *
-	 * @var int
-	 */
-	public $created_on;
+    /**
+     *
+     * @var int
+     */
+    public $created_on;
 
-	/**
-	 *
-	 * @var int
-	 */
-	public $updated_on;
+    /**
+     *
+     * @var int
+     */
+    public $updated_on;
 
-	/**
-	 *
-	 * @var string
-	 */
-	public $title;
+    /**
+     *
+     * @var string
+     */
+    public $title;
 
-	/**
-	 *
-	 * @var bool
-	 */
-	public $all_events;
+    /**
+     *
+     * @var bool
+     */
+    public $all_events;
 
-	/**
-	 *
-	 * @var string
-	 */
-	public $public_key;
+    /**
+     *
+     * @var string
+     */
+    public $public_key;
 
-	/**
-	 *
-	 * @var string[]
-	 */
-	public $events;
+    /**
+     *
+     * @var string[]
+     */
+    public $events;
 
-	/**
-	 *
-	 * @var string
-	 */
-	public $callback;
+    /**
+     *
+     * @var string
+     */
+    public $callback;
 
-	#[\ReturnTypeWillChange]
-	public function jsonSerialize() {
-		return array_filter((array) $this);
-	}
-}
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $webhook = new self();
+        $webhook->type = $data['type'] ?? '';
+        $webhook->id = $data['id'] ?? '';
+        $webhook->created_on = $data['created_on'] ?? 0;
+        $webhook->updated_on = $data['updated_on'] ?? 0;
+        $webhook->title = $data['title'] ?? '';
+        $webhook->all_events = $data['all_events'] ?? false;
+        $webhook->public_key = $data['public_key'] ?? '';
+        $webhook->events = $data['events'] ?? [];
+        $webhook->callback = $data['callback'] ?? '';
 
+        return $webhook;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Model/WebhookList.php b/lib/Model/WebhookList.php
new file mode 100644
index 0000000..ffbe8ba
--- /dev/null
+++ b/lib/Model/WebhookList.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace Chip\Model;
+
+class WebhookList implements \JsonSerializable
+{
+    /** @var Webhook[]|null */
+    public $results;
+
+    /** @var string|null */
+    public $next;
+
+    /** @var string|null */
+    public $previous;
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    public static function fromArray(array $data): self
+    {
+        $list = new self();
+        $list->results = array_map(
+            fn (array $w) => Webhook::fromArray($w),
+            $data['results'] ?? []
+        );
+        $list->next = $data['next'] ?? null;
+        $list->previous = $data['previous'] ?? null;
+
+        return $list;
+    }
+
+    #[\ReturnTypeWillChange]
+    public function jsonSerialize()
+    {
+        return array_filter((array) $this);
+    }
+}
diff --git a/lib/Resource/AccountResource.php b/lib/Resource/AccountResource.php
new file mode 100644
index 0000000..e7aa1d6
--- /dev/null
+++ b/lib/Resource/AccountResource.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+
+final class AccountResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    /**
+     * @param array<string, mixed> $filters
+     * @return array<string, mixed>
+     */
+    public function balance(array $filters = []): array
+    {
+        $response = $this->client->request('GET', 'account/json/balance/', [
+            'query' => $filters,
+        ]);
+
+        $json = json_encode($response);
+
+        return json_decode($json !== false ? $json : '[]', true);
+    }
+
+    /**
+     * @param array<string, mixed> $filters
+     * @return array<string, mixed>
+     */
+    public function turnover(array $filters = []): array
+    {
+        $response = $this->client->request('GET', 'account/json/turnover/', [
+            'query' => $filters,
+        ]);
+
+        $json = json_encode($response);
+
+        return json_decode($json !== false ? $json : '[]', true);
+    }
+}
diff --git a/lib/Resource/BillingResource.php b/lib/Resource/BillingResource.php
new file mode 100644
index 0000000..14e85b3
--- /dev/null
+++ b/lib/Resource/BillingResource.php
@@ -0,0 +1,146 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+use Chip\Model\Billing\BillingTemplate;
+use Chip\Model\Billing\BillingTemplateClient;
+use Chip\Model\Billing\BillingTemplateClientAddSubscriber;
+use Chip\Model\Billing\BillingTemplateClientList;
+use Chip\Model\Billing\BillingTemplateList;
+use Chip\Model\Purchase;
+
+final class BillingResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    /**
+     * @return array<string, mixed>|\stdClass
+     */
+    public function create(BillingTemplate $billing): array|\stdClass
+    {
+        return $this->client->request('POST', 'billing/', [
+            'json' => $billing,
+        ]);
+    }
+
+    public function createTemplate(BillingTemplate $billing): BillingTemplate
+    {
+        $response = $this->client->request('POST', 'billing_templates/', [
+            'json' => $billing,
+        ]);
+
+        return BillingTemplate::fromArray((array) $response);
+    }
+
+    public function listTemplates(): BillingTemplateList
+    {
+        $response = $this->client->request('GET', 'billing_templates/');
+
+        return BillingTemplateList::fromArray((array) $response);
+    }
+
+    /**
+     * @return \Generator<int, BillingTemplate>
+     */
+    public function iterateTemplates(): \Generator
+    {
+        $url = 'billing_templates/';
+
+        while ($url !== null) {
+            $response = $this->client->request('GET', $url);
+            $list = BillingTemplateList::fromArray((array) $response);
+
+            foreach ($list->results ?? [] as $template) {
+                yield $template;
+            }
+
+            $url = $list->next;
+        }
+    }
+
+    public function getTemplate(string $billingId): BillingTemplate
+    {
+        $response = $this->client->request('GET', "billing_templates/$billingId/");
+
+        return BillingTemplate::fromArray((array) $response);
+    }
+
+    public function updateTemplate(string $billingId, BillingTemplate $billing): BillingTemplate
+    {
+        $response = $this->client->request('PUT', "billing_templates/$billingId/", [
+            'json' => $billing,
+        ]);
+
+        return BillingTemplate::fromArray((array) $response);
+    }
+
+    public function deleteTemplate(string $billingId): void
+    {
+        $this->client->request('DELETE', "billing_templates/$billingId/");
+    }
+
+    public function sendInvoice(string $billingId, BillingTemplateClient $client): Purchase
+    {
+        $response = $this->client->request('POST', "billing_templates/$billingId/send_invoice/", [
+            'json' => $client,
+        ]);
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function addSubscriber(string $billingId, BillingTemplateClient $client): BillingTemplateClientAddSubscriber
+    {
+        $response = $this->client->request('POST', "billing_templates/$billingId/add_subscriber/", [
+            'json' => $client,
+        ]);
+
+        return BillingTemplateClientAddSubscriber::fromArray((array) $response);
+    }
+
+    public function listClients(string $billingId): BillingTemplateClientList
+    {
+        $response = $this->client->request('GET', "billing_templates/$billingId/clients/");
+
+        return BillingTemplateClientList::fromArray((array) $response);
+    }
+
+    /**
+     * @return \Generator<int, BillingTemplateClient>
+     */
+    public function iterateClients(string $billingId): \Generator
+    {
+        $url = "billing_templates/$billingId/clients/";
+
+        while ($url !== null) {
+            $response = $this->client->request('GET', $url);
+            $list = BillingTemplateClientList::fromArray((array) $response);
+
+            foreach ($list->results ?? [] as $client) {
+                yield $client;
+            }
+
+            $url = $list->next;
+        }
+    }
+
+    public function getClient(string $billingId, string $clientId): BillingTemplateClient
+    {
+        $response = $this->client->request('GET', "billing_templates/$billingId/clients/$clientId/");
+
+        return BillingTemplateClient::fromArray((array) $response);
+    }
+
+    public function updateClient(string $billingId, string $clientId, BillingTemplateClient $client): BillingTemplateClient
+    {
+        $response = $this->client->request('PATCH', "billing_templates/$billingId/clients/$clientId/", [
+            'json' => $client,
+        ]);
+
+        return BillingTemplateClient::fromArray((array) $response);
+    }
+}
diff --git a/lib/Resource/ClientsResource.php b/lib/Resource/ClientsResource.php
new file mode 100644
index 0000000..0afac8f
--- /dev/null
+++ b/lib/Resource/ClientsResource.php
@@ -0,0 +1,102 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+use Chip\Model\ClientDetails;
+use Chip\Model\ClientList;
+use Chip\Model\ClientRecurringToken;
+use Chip\Model\ClientRecurringTokenList;
+
+final class ClientsResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    public function create(ClientDetails $client): ClientDetails
+    {
+        $response = $this->client->request('POST', 'clients/', [
+            'json' => $client,
+        ]);
+
+        return ClientDetails::fromArray((array) $response);
+    }
+
+    public function list(): ClientList
+    {
+        $response = $this->client->request('GET', 'clients/');
+
+        return ClientList::fromArray((array) $response);
+    }
+
+    /**
+     * @return \Generator<int, ClientDetails>
+     */
+    public function iterate(): \Generator
+    {
+        $url = 'clients/';
+
+        while ($url !== null) {
+            $response = $this->client->request('GET', $url);
+            $list = ClientList::fromArray((array) $response);
+
+            foreach ($list->results ?? [] as $client) {
+                yield $client;
+            }
+
+            $url = $list->next;
+        }
+    }
+
+    public function get(string $clientId): ClientDetails
+    {
+        $response = $this->client->request('GET', "clients/$clientId/");
+
+        return ClientDetails::fromArray((array) $response);
+    }
+
+    public function update(string $clientId, ClientDetails $client): ClientDetails
+    {
+        $response = $this->client->request('PUT', "clients/$clientId/", [
+            'json' => $client,
+        ]);
+
+        return ClientDetails::fromArray((array) $response);
+    }
+
+    public function partialUpdate(string $clientId, ClientDetails $client): ClientDetails
+    {
+        $response = $this->client->request('PATCH', "clients/$clientId/", [
+            'json' => $client,
+        ]);
+
+        return ClientDetails::fromArray((array) $response);
+    }
+
+    public function delete(string $clientId): void
+    {
+        $this->client->request('DELETE', "clients/$clientId/");
+    }
+
+    public function listRecurringTokens(string $clientId): ClientRecurringTokenList
+    {
+        $response = $this->client->request('GET', "clients/$clientId/recurring_tokens/");
+
+        return ClientRecurringTokenList::fromArray((array) $response);
+    }
+
+    public function getRecurringToken(string $clientId, string $purchaseId): ClientRecurringToken
+    {
+        $response = $this->client->request('GET', "clients/$clientId/recurring_tokens/$purchaseId/");
+
+        return ClientRecurringToken::fromArray((array) $response);
+    }
+
+    public function deleteRecurringToken(string $clientId, string $purchaseId): void
+    {
+        $this->client->request('DELETE', "clients/$clientId/recurring_tokens/$purchaseId/");
+    }
+}
diff --git a/lib/Resource/PaymentMethodsResource.php b/lib/Resource/PaymentMethodsResource.php
new file mode 100644
index 0000000..d012b2d
--- /dev/null
+++ b/lib/Resource/PaymentMethodsResource.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+use Chip\Model\PaymentMethods;
+
+final class PaymentMethodsResource
+{
+    public function __construct(
+        private readonly ClientInterface $client,
+        private readonly string $brandId,
+    ) {
+    }
+
+    /**
+     * @param array<string, mixed> $options
+     */
+    public function list(string $currency = 'MYR', array $options = []): PaymentMethods
+    {
+        $response = $this->client->request('GET', 'payment_methods/', [
+            'query' => array_merge([
+                'brand_id' => $this->brandId,
+                'currency' => $currency,
+            ], $options),
+        ]);
+
+        return PaymentMethods::fromArray((array) $response);
+    }
+}
diff --git a/lib/Resource/PublicKeyResource.php b/lib/Resource/PublicKeyResource.php
new file mode 100644
index 0000000..306eced
--- /dev/null
+++ b/lib/Resource/PublicKeyResource.php
@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+
+final class PublicKeyResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    public function get(): string
+    {
+        $response = $this->client->request('GET', 'public_key/');
+        $arr = (array) $response;
+
+        return $arr['public_key'] ?? '';
+    }
+}
diff --git a/lib/Resource/PurchasesResource.php b/lib/Resource/PurchasesResource.php
new file mode 100644
index 0000000..6edbde9
--- /dev/null
+++ b/lib/Resource/PurchasesResource.php
@@ -0,0 +1,104 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+use Chip\Model\Purchase;
+
+final class PurchasesResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    public function create(Purchase $purchase): Purchase
+    {
+        $response = $this->client->request('POST', 'purchases/', [
+            'json' => $purchase,
+        ]);
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function get(string $purchaseId): Purchase
+    {
+        $response = $this->client->request('GET', "purchases/$purchaseId/");
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function cancel(string $purchaseId): Purchase
+    {
+        $response = $this->client->request('POST', "purchases/$purchaseId/cancel/");
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function release(string $purchaseId): Purchase
+    {
+        $response = $this->client->request('POST', "purchases/$purchaseId/release/");
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function capture(string $purchaseId, ?int $amount = null): Purchase
+    {
+        $options = [];
+        if ($amount !== null) {
+            $options['json'] = ['amount' => $amount];
+        }
+
+        $response = $this->client->request('POST', "purchases/$purchaseId/capture/", $options);
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function charge(string $purchaseId, string $token): Purchase
+    {
+        $response = $this->client->request('POST', "purchases/$purchaseId/charge/", [
+            'json' => ['recurring_token' => $token],
+        ]);
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function deleteRecurringToken(string $purchaseId): Purchase
+    {
+        $response = $this->client->request('POST', "purchases/$purchaseId/delete_recurring_token/");
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function refund(string $purchaseId, ?int $amount = null): Purchase
+    {
+        $options = [];
+        if ($amount !== null) {
+            $options['json'] = ['amount' => $amount];
+        }
+
+        $response = $this->client->request('POST', "purchases/$purchaseId/refund/", $options);
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function markAsPaid(string $purchaseId, ?int $utcTimestamp = null): Purchase
+    {
+        $options = [];
+        if ($utcTimestamp !== null) {
+            $options['json'] = ['paid_on' => $utcTimestamp];
+        }
+
+        $response = $this->client->request('POST', "purchases/$purchaseId/mark_as_paid/", $options);
+
+        return Purchase::fromArray((array) $response);
+    }
+
+    public function resendInvoice(string $purchaseId): Purchase
+    {
+        $response = $this->client->request('POST', "purchases/$purchaseId/resend_invoice/");
+
+        return Purchase::fromArray((array) $response);
+    }
+}
diff --git a/lib/Resource/StatementsResource.php b/lib/Resource/StatementsResource.php
new file mode 100644
index 0000000..65ad66b
--- /dev/null
+++ b/lib/Resource/StatementsResource.php
@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+use Chip\Model\CompanyStatement;
+use Chip\Model\CompanyStatementList;
+
+final class StatementsResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    /**
+     * @param array<string, mixed> $filters
+     */
+    public function schedule(CompanyStatement $statement, array $filters = []): CompanyStatement
+    {
+        $response = $this->client->request('POST', 'company_statements/', [
+            'query' => $filters,
+            'json' => $statement,
+        ]);
+
+        return CompanyStatement::fromArray((array) $response);
+    }
+
+    public function list(): CompanyStatementList
+    {
+        $response = $this->client->request('GET', 'company_statements/');
+
+        return CompanyStatementList::fromArray((array) $response);
+    }
+
+    /**
+     * @return \Generator<int, CompanyStatement>
+     */
+    public function iterate(): \Generator
+    {
+        $url = 'company_statements/';
+
+        while ($url !== null) {
+            $response = $this->client->request('GET', $url);
+            $list = CompanyStatementList::fromArray((array) $response);
+
+            foreach ($list->results ?? [] as $statement) {
+                yield $statement;
+            }
+
+            $url = $list->next;
+        }
+    }
+
+    public function get(string $statementId): CompanyStatement
+    {
+        $response = $this->client->request('GET', "company_statements/$statementId/");
+
+        return CompanyStatement::fromArray((array) $response);
+    }
+
+    public function cancel(string $statementId): CompanyStatement
+    {
+        $response = $this->client->request('POST', "company_statements/$statementId/cancel/");
+
+        return CompanyStatement::fromArray((array) $response);
+    }
+}
diff --git a/lib/Resource/WebhooksResource.php b/lib/Resource/WebhooksResource.php
new file mode 100644
index 0000000..e66d50b
--- /dev/null
+++ b/lib/Resource/WebhooksResource.php
@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Chip\Resource;
+
+use Chip\Http\ClientInterface;
+use Chip\Model\Webhook;
+use Chip\Model\WebhookList;
+
+final class WebhooksResource
+{
+    public function __construct(private readonly ClientInterface $client)
+    {
+    }
+
+    public function create(Webhook $webhook): Webhook
+    {
+        $response = $this->client->request('POST', 'webhooks/', [
+            'json' => $webhook,
+        ]);
+
+        return Webhook::fromArray((array) $response);
+    }
+
+    public function list(): WebhookList
+    {
+        $response = $this->client->request('GET', 'webhooks/');
+
+        return WebhookList::fromArray((array) $response);
+    }
+
+    /**
+     * @return \Generator<int, Webhook>
+     */
+    public function iterate(): \Generator
+    {
+        $url = 'webhooks/';
+
+        while ($url !== null) {
+            $response = $this->client->request('GET', $url);
+            $list = WebhookList::fromArray((array) $response);
+
+            foreach ($list->results ?? [] as $webhook) {
+                yield $webhook;
+            }
+
+            $url = $list->next;
+        }
+    }
+
+    public function get(string $webhookId): Webhook
+    {
+        $response = $this->client->request('GET', "webhooks/$webhookId/");
+
+        return Webhook::fromArray((array) $response);
+    }
+
+    public function update(string $webhookId, Webhook $webhook): Webhook
+    {
+        $response = $this->client->request('PUT', "webhooks/$webhookId/", [
+            'json' => $webhook,
+        ]);
+
+        return Webhook::fromArray((array) $response);
+    }
+
+    public function partialUpdate(string $webhookId, Webhook $webhook): Webhook
+    {
+        $response = $this->client->request('PATCH', "webhooks/$webhookId/", [
+            'json' => $webhook,
+        ]);
+
+        return Webhook::fromArray((array) $response);
+    }
+
+    public function delete(string $webhookId): void
+    {
+        $this->client->request('DELETE', "webhooks/$webhookId/");
+    }
+}
diff --git a/lib/Traits/Api/Billing.php b/lib/Traits/Api/Billing.php
deleted file mode 100644
index cb2325f..0000000
--- a/lib/Traits/Api/Billing.php
+++ /dev/null
@@ -1,113 +0,0 @@
-<?php
-
-namespace Chip\Traits\Api;
-
-use Chip\Model\Billing\BillingTemplate;
-use Chip\Model\Billing\BillingTemplateClient;
-use Chip\Model\Billing\BillingTemplateClientAddSubscriber;
-use Chip\Model\Billing\BillingTemplateClientList;
-use Chip\Model\Billing\BillingTemplateList;
-use Chip\Model\Purchase;
-
-trait Billing
-{
-	/**
-	 * Send an invoice to one or several clients.
-	 */
-	public function createBilling(BillingTemplate $billing)
-	{
-		return $this->request('POST', 'billing/', [
-			'json' => $billing
-		]);
-	}
-
-	/**
-	 * Create a template to issue repeated invoices from in the future, with or without a subscription.
-	 */
-	public function createBillingTemplate(BillingTemplate $billing)
-	{
-		return $this->mapper->map($this->request('POST', 'billing_templates/', [
-			'json' => $billing
-		]), new BillingTemplate());
-	}
-
-	/**
-	 * List all billing templates.
-	 */
-	public function getBillingTemplates()
-	{
-		return $this->mapper->map($this->request('GET', 'billing_templates/'), new BillingTemplateList());
-	}
-
-	/**
-	 * Retrieve a billing template by ID.
-	 */
-	public function getBillingTemplate(string $billing_id)
-	{
-		return $this->mapper->map($this->request('GET', "billing_templates/$billing_id/"), new BillingTemplate());
-	}
-
-	/**
-	 * Update a billing template by ID.
-	 */
-	public function updateBillingTemplate(string $billing_id, BillingTemplate $billing)
-	{
-		return $this->mapper->map($this->request('PUT', "billing_templates/$billing_id/", [
-			'json' => $billing
-		]), new BillingTemplate());
-	}
-
-	/**
-	 * Delete a billing template by ID.
-	 */
-	public function deleteBillingTemplate(string $billing_id)
-	{
-		return $this->request('DELETE', "billing_templates/$billing_id/");
-	}
-
-	/**
-	 * Send an invoice, generating a purchase from billing template data.
-	 */
-	public function sendBillingTemplateInvoice(string $billing_id, BillingTemplateClient $billingTemplateClient)
-	{
-		return $this->mapper->map($this->request('POST', "billing_templates/$billing_id/send_invoice/", [
-			'json' => $billingTemplateClient
-		]), new Purchase());
-	}
-
-	/**
-	 * Add a billing template client and activate recurring billing (is_subscription: true).
-	 */
-	public function addBillingTemplateSubscriber(string $billing_id, BillingTemplateClient $billingTemplateClient)
-	{
-		return $this->mapper->map($this->request('POST', "billing_templates/$billing_id/add_subscriber/", [
-			'json' => $billingTemplateClient
-		]), new BillingTemplateClientAddSubscriber());
-	}
-
-	/**
-	 * List all billing template clients for this billing template.
-	 */
-	public function getBillingTemplateClients(string $billing_id)
-	{
-		return $this->mapper->map($this->request('GET', "billing_templates/$billing_id/clients/"), new BillingTemplateClientList());
-	}
-
-	/**
-	 * Retrieve a billing template client by client's ID.
-	 */
-	public function getBillingTemplateClient(string $billing_id, string $billing_client_id)
-	{
-		return $this->mapper->map($this->request('GET', "billing_templates/$billing_id/clients/$billing_client_id/"), new BillingTemplateClient());
-	}
-
-	/**
-	 * Partially update a billing template client by client's ID.
-	 */
-	public function updateBillingTemplateClient(string $billing_id, string $billing_client_id, BillingTemplateClient $billingTemplateClient)
-	{
-		return $this->mapper->map($this->request('PATCH', "billing_templates/$billing_id/clients/$billing_client_id/", [
-			'json' => $billingTemplateClient
-		]), new BillingTemplateClient());
-	}
-}
diff --git a/lib/Traits/Api/Client.php b/lib/Traits/Api/Client.php
deleted file mode 100644
index 343c2c2..0000000
--- a/lib/Traits/Api/Client.php
+++ /dev/null
@@ -1,26 +0,0 @@
-<?php
-
-namespace Chip\Traits\Api;
-
-use Chip\Model\ClientDetails as ModelClientDetails;
-use Chip\Model\ClientList;
-
-trait Client
-{
-	/**
-	 * 
-	 * @param \Chip\Model\ClientDetails $client
-	 * @return \Chip\Model\ClientDetails
-	 */
-	public function createClient(ModelClientDetails $client): ModelClientDetails
-	{
-		return $this->mapper->map($this->request('POST', 'clients/', [
-			'json' => $client
-		]), new ModelClientDetails());
-	}
-
-	public function getClients()
-	{
-		return $this->mapper->map($this->request('GET', 'clients/'), new ClientList());
-	}
-}
diff --git a/lib/Traits/Api/PaymentMethod.php b/lib/Traits/Api/PaymentMethod.php
deleted file mode 100644
index 54595b9..0000000
--- a/lib/Traits/Api/PaymentMethod.php
+++ /dev/null
@@ -1,23 +0,0 @@
-<?php
-
-namespace Chip\Traits\Api;
-
-use Chip\Model\PaymentMethods as ModelPaymentMethods;
-
-trait PaymentMethod
-{
-	/**
-	 * 
-	 * @param string $currency
-	 * @return \Chip\Model\PaymentMethods
-	 */
-	public function getPaymentMethods(string $currency = 'MYR'): ModelPaymentMethods
-	{
-		return $this->mapper->map($this->request('GET', 'payment_methods/', [
-			'query' => [
-				'brand_id' => $this->brandId,
-				'currency' => $currency
-			]
-		]), new ModelPaymentMethods());
-	}
-}
\ No newline at end of file
diff --git a/lib/Traits/Api/Purchase.php b/lib/Traits/Api/Purchase.php
deleted file mode 100644
index 6b1d3e5..0000000
--- a/lib/Traits/Api/Purchase.php
+++ /dev/null
@@ -1,126 +0,0 @@
-<?php
-
-namespace Chip\Traits\Api;
-
-use Chip\Model\Purchase as ModelPurchase;
-
-trait Purchase
-{
-	/**
-	 * 
-	 * @param \Chip\Model\Purchase $purchase
-	 * @return \Chip\Model\Purchase
-	 */
-	public function createPurchase(ModelPurchase $purchase): ModelPurchase
-	{
-		return $this->mapper->map($this->request('POST', 'purchases/', [
-			'json' => $purchase
-		]), new ModelPurchase());
-	}
-	
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @return \Chip\Model\Purchase
-	 */
-	public function getPurchase(string $purchaseId): ModelPurchase
-	{
-		return $this->mapper->map($this->request('GET', "purchases/$purchaseId/"), new ModelPurchase());
-	}
-	
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @return \Chip\Model\Purchase
-	 */
-	public function cancelPurchase(string $purchaseId): ModelPurchase
-	{
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/cancel/"), new ModelPurchase());
-	}
-	
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @return \Chip\Model\Purchase
-	 */
-	public function releasePurchase(string $purchaseId): ModelPurchase
-	{
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/release/"), new ModelPurchase());
-	}
-	
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @param int $amount
-	 * @return \Chip\Model\Purchase
-	 */
-	public function capturePurchase(string $purchaseId, ?int $amount = null): ModelPurchase
-	{
-		$options = [];
-		if ($amount !== null) {
-			$options['json'] = [
-				'amount' => $amount
-			];
-		}
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/capture/", $options), new ModelPurchase());
-	}
-	
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @param string $token
-	 * @return \Chip\Model\Purchase
-	 */
-	public function chargePurchase(string $purchaseId, string $token): ModelPurchase
-	{
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/charge/", [
-			'json' => [
-				'recurring_token' => $token
-			]
-		]), new ModelPurchase());
-	}
-
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @return \Chip\Model\Purchase
-	 */
-	public function deleteRecurringToken(string $purchaseId): ModelPurchase
-	{
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/delete_recurring_token/"), new ModelPurchase());
-	}
-	
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @param int $amount
-	 * @return \Chip\Model\Purchase
-	 */
-	public function refundPurchase(string $purchaseId, ?int $amount = null): ModelPurchase
-	{
-		$options = [];
-		if ($amount !== null) {
-			$options['json'] = [
-				'amount' => $amount
-			];
-		}
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/refund/", $options), new ModelPurchase());
-	}
-
-	/**
-	 * 
-	 * @param string $purchaseId
-	 * @param int $utcTimestamp
-	 * @return \Chip\Model\Purchase
-	 */
-	public function markAsPaid(string $purchaseId, ?int $utcTimestamp = null): ModelPurchase
-	{
-		$options = [];
-		if ($utcTimestamp !== null) {
-			$options['json'] = [
-				'paid_on' => $utcTimestamp
-			];
-		}
-		return $this->mapper->map($this->request('POST', "purchases/$purchaseId/mark_as_paid/", $options), new ModelPurchase());
-	}
-}
\ No newline at end of file
diff --git a/lib/Traits/Api/Webhook.php b/lib/Traits/Api/Webhook.php
deleted file mode 100644
index 5095d38..0000000
--- a/lib/Traits/Api/Webhook.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-namespace Chip\Traits\Api;
-
-use Chip\Model\Webhook as ModelWebHook;
-
-trait Webhook
-{
-	/**
-	 * 
-	 * @param \Chip\Model\Webhook $webhook
-	 * @return \Chip\Model\Webhook
-	 */
-	public function createWebhook(ModelWebHook $webhook): ModelWebHook
-	{
-		return $this->mapper->map($this->request('POST', 'webhooks/', [
-			'json' => $webhook
-		]), new ModelWebHook());
-	}
-
-	/**
-	 * 
-	 * @param string $webhookId
-	 * @return \Chip\Model\Webhook
-	 */
-	public function getWebhook(string $webhookId): ModelWebHook
-	{
-		return $this->mapper->map($this->request('GET', "webhooks/$webhookId/"), new ModelWebHook());
-	}
-
-	/**
-	 * 
-	 * @param string $webhookId
-	 * @return mixed
-	 */
-	public function deleteWebhook(string $webhookId): mixed
-	{
-		return $this->request('DELETE', "webhooks/$webhookId/");
-	}
-}
\ No newline at end of file
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..81c2ea3
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,9 @@
+includes:
+    - vendor/phpstan/phpstan/conf/bleedingEdge.neon
+
+parameters:
+    level: 8
+    paths:
+        - lib
+        - tests
+    ignoreErrors:
diff --git a/scripts/generate_pr_summary.py b/scripts/generate_pr_summary.py
new file mode 100644
index 0000000..103d6dd
--- /dev/null
+++ b/scripts/generate_pr_summary.py
@@ -0,0 +1,99 @@
+import os
+import sys
+import requests
+
+
+def generate_summary(diff_text: str, current_body: str, api_key: str, model: str = "gemini-3-flash-preview:cloud") -> str:
+    url = os.getenv("OLLAMA_API_URL", "https://api.ollama.com/api/generate")
+
+    prompt = f"""You are a senior software engineer. Please review the following git diff and generate a Pull Request description.
+
+Current PR Body (if any):
+{current_body}
+
+Git Diff:
+{diff_text}
+
+Please generate a Pull Request description that follows this exact format:
+
+## What does this change?
+[Provide a detailed explanation of WHAT the problem was and HOW this change solves it. Focus on the 'why' and 'how'.]
+
+## Asana / Jira / Trello task link
+<!-- Provide Asana / Jira / Trello task link here -->
+
+## How to test
+[Provide step-by-step instructions to help others verify the change. Suggest specific tests based on the modified files.]
+
+## Potential Risks & Senior Review Items
+[Identify potential side effects, performance implications, security considerations, or architectural concerns. Highlight specific areas where a senior engineer should focus their review.]
+
+## Is this PR warrant an automatic approval?
+[Yes/No. Provide a brief justification based on the complexity and risk of the changes.]
+
+## Images
+<!-- Usually only applicable to UI changes, what did it look like before and what will it look like after? -->
+
+Important:
+- If the 'Current PR Body' already contains information (like task links or images), PRESERVE them in the new summary.
+- Fill in the 'What does this change?', 'How to test', 'Potential Risks & Senior Review Items', and 'Is this PR warrant an automatic approval?' sections based on the provided diff.
+- Keep the other sections exactly as shown (with their HTML comments/placeholders) so the user can fill them in manually if needed.
+- Return ONLY the markdown content.
+"""
+
+    headers = {
+        "Authorization": f"Bearer {api_key}",
+        "Content-Type": "application/json",
+    }
+
+    data = {
+        "model": model,
+        "prompt": prompt,
+        "stream": False,
+    }
+
+    try:
+        response = requests.post(url, headers=headers, json=data, timeout=90)
+        response.raise_for_status()
+        result = response.json()
+        return result.get("response", "Could not generate summary.")
+    except requests.exceptions.RequestException as e:
+        return f"Error calling Ollama API: {e!s}"
+
+
+def main() -> int:
+    if len(sys.argv) < 2:
+        print("Usage: python generate_pr_summary.py <diff_file> [current_body_file]")
+        return 1
+
+    diff_file = sys.argv[1]
+    current_body_file = sys.argv[2] if len(sys.argv) > 2 else None
+
+    api_key = os.getenv("OLLAMA_API_KEY")
+    if not api_key:
+        print("Error: OLLAMA_API_KEY environment variable not set.")
+        return 1
+
+    if not os.path.exists(diff_file):
+        print(f"Error: File {diff_file} not found.")
+        return 1
+
+    with open(diff_file, encoding="utf-8") as f:
+        diff_text = f.read()
+
+    current_body = ""
+    if current_body_file and os.path.exists(current_body_file):
+        with open(current_body_file, encoding="utf-8") as f:
+            current_body = f.read()
+
+    # Limit diff size to avoid token limits
+    if len(diff_text) > 50000:
+        diff_text = diff_text[:50000] + "\n\n... (diff truncated for size) ..."
+
+    summary = generate_summary(diff_text, current_body, api_key)
+    print(summary)
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/test.php b/test.php
deleted file mode 100644
index c8d1524..0000000
--- a/test.php
+++ /dev/null
@@ -1,82 +0,0 @@
-<?php
-
-use Chip\Model\Billing\BillingTemplate;
-use Chip\Model\Billing\BillingTemplateClient;
-
-require_once 'vendor/autoload.php';
-$env = parse_ini_file('.env');
-
-$purchase_id = "14483a7f-2bde-4e9d-a3d2-ffa6e09e72d7";
-$billing_template_id = "e0aff507-a282-410b-8c82-a74d1cc44fd1";
-
-$chip = new \Chip\ChipApi($env["BRAND_ID"], $env["API_KEY"], 'https://gate.chip-in.asia/api/v1/');
-// $client = new \Chip\Model\ClientDetails();
-// $client->email = 'test@example.com';
-// $purchase = new \Chip\Model\Purchase();
-// $purchase->client = $client;
-// $details = new \Chip\Model\PurchaseDetails();
-// $product = new \Chip\Model\Product();
-// $product->name = 'test product ' . date('Y-m-d H:i:s e');
-// $product->price = 100;
-// $details->products = [$product];
-// $purchase->purchase = $details;
-// $purchase->brand_id = $env["BRAND_ID"];
-// $purchase->success_redirect = 'https://yourdomain.com/redirect.php?success=1';
-// $purchase->success_callback = 'https://yourdomain.com/callback.php?success=0';
-// $purchase->failure_redirect = 'https://yourdomain.com/redirect.php?success=0';
-
-/** Billing */
-$billing = new BillingTemplate();
-
-// $client = new BillingTemplateClient();
-// $client->client_id = "6c761052-b64e-48f4-a68b-b0b7ef1935a2";
-// $billing->clients = [$client];
-
-$purchaseDetails = new \Chip\Model\PurchaseDetails();
-$product = new \Chip\Model\Product();
-$product->name = 'test product ' . date('Y-m-d H:i:s e');
-$product->price = 100;
-$purchaseDetails->products = [$product];
-$billing->purchase = $purchaseDetails;
-// $billing->is_subscription = true;
-$billing->brand_id = $env["BRAND_ID"];
-// $billing->invoice_due = time() + 100;
-// $billing->title = 'test createBillingTemplate ' . date('Y-m-d H:i:s e');
-// $result = $chip->getClients();
-// $result = $chip->createBilling($billing);
-
-// $billing->subscription_period = 1;
-// $billing->subscription_period_units = "months";
-$billing->subscription_due_period = 7;
-$billing->subscription_due_period_units = "days";
-// $billing->subscription_charge_period_end = true;
-// $billing->subscription_trial_periods = 1;
-$billing->subscription_active = true;
-// $result = $chip->createBillingTemplate($billing);
-
-$result = $chip->getBillingTemplates();
-
-// $result = $chip->getBillingTemplate("bab94920-5078-4b08-9cbc-13e78549652f");
-
-// $billing->title = 'test updateBillingTemplate ' . date('Y-m-d H:i:s e');
-// $result = $chip->updateBillingTemplate("bab94920-5078-4b08-9cbc-13e78549652f", $billing);
-
-// $result = $chip->deleteBillingTemplate("d2ee0722-c3ac-40da-a3f3-b9cd8084c596");
-
-// $billing_client = new BillingTemplateClient();
-// $billing_client->client_id = "6c761052-b64e-48f4-a68b-b0b7ef1935a2";
-// $result = $chip->sendBillingTemplateInvoice("d2ee0722-c3ac-40da-a3f3-b9cd8084c596", $billing_client);
-
-// $billing_client = new BillingTemplateClient();
-// $billing_client->client_id = "6c761052-b64e-48f4-a68b-b0b7ef1935a2";
-// $result = $chip->addBillingTemplateSubscriber("d2ee0722-c3ac-40da-a3f3-b9cd8084c596", $billing_client);
-
-// $result = $chip->getBillingTemplateClients("d2ee0722-c3ac-40da-a3f3-b9cd8084c596");
-
-// $result = $chip->getBillingTemplateClient("d2ee0722-c3ac-40da-a3f3-b9cd8084c596", "3efa3608-67cf-40fc-bed4-b55da4c87eb8");
-
-$billing_client = new BillingTemplateClient();
-$billing_client->status = 'active';
-$result = $chip->updateBillingTemplateClient("d2ee0722-c3ac-40da-a3f3-b9cd8084c596", "3efa3608-67cf-40fc-bed4-b55da4c87eb8", $billing_client);
-
-var_dump($result);
diff --git a/tests/ApiTest.php b/tests/ApiTest.php
index 0c087f2..b0d1882 100644
--- a/tests/ApiTest.php
+++ b/tests/ApiTest.php
@@ -1,4 +1,6 @@
-<?php declare(strict_types=1);
+<?php
+
+declare(strict_types=1);
 
 use GuzzleHttp\Handler\MockHandler;
 use GuzzleHttp\HandlerStack;
@@ -6,194 +8,1013 @@
 use GuzzleHttp\Psr7\Response;
 use PHPUnit\Framework\TestCase;
 
-use Chip\Model\Purchase as ModelPurchase;
-
-class ApiTest extends TestCase
+final class ApiTest extends TestCase
 {
-	public $purchase_id = "14483a7f-2bde-4e9d-a3d2-ffa6e09e72d7";
-
-	public function testRefundWithoutAmount() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->refundPurchase($this->purchase_id);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/refund", $transaction['request']->getUri()->getPath());
-		$this->assertEmpty($transaction['request']->getBody()->getContents());
-	}
-	
-	public function testRefundWithAmount() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->refundPurchase($this->purchase_id, 100);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/refund", $transaction['request']->getUri()->getPath());
-		$body = json_decode($transaction['request']->getBody()->getContents(), true);
-		$this->assertEquals(100, $body['amount']);
-	}
-	
-	public function testPaymentMethods() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->getPaymentMethods('USD');
-		$transaction = $container[0];
-		
-		$this->assertEquals('GET', $transaction['request']->getMethod());
-		$this->assertStringContainsString('payment_methods/', $transaction['request']->getUri()->getPath());
-		$body = json_decode($transaction['request']->getBody()->getContents(), true);
-		$this->assertStringContainsString('currency=USD', $transaction['request']->getUri()->getQuery());
-	}
-	
-	public function testCreatePurchase() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$model = new ModelPurchase();
-		$api->createPurchase($model);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString('purchases/', $transaction['request']->getUri()->getPath());
-	}
-	
-	public function testGetPurchase() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->getPurchase($this->purchase_id);
-		$transaction = $container[0];
-		
-		$this->assertEquals('GET', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/", $transaction['request']->getUri()->getPath());
-	}
-	
-	public function testCancelPurchase() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->cancelPurchase($this->purchase_id);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/cancel", $transaction['request']->getUri()->getPath());
-	}
-	
-	public function testRelasePurchase() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->releasePurchase($this->purchase_id);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/release", $transaction['request']->getUri()->getPath());
-	}
-	
-	public function testCaptureWithoutAmount() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->capturePurchase($this->purchase_id);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/capture", $transaction['request']->getUri()->getPath());
-		$this->assertEmpty($transaction['request']->getBody()->getContents());
-	}
-	
-	public function testCaptureWithAmount() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->capturePurchase($this->purchase_id, 100);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/capture", $transaction['request']->getUri()->getPath());
-		$body = json_decode($transaction['request']->getBody()->getContents(), true);
-		$this->assertEquals(100, $body['amount']);
-	}
-	
-	public function testChargePurchase() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->chargePurchase($this->purchase_id, 'token');
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/charge", $transaction['request']->getUri()->getPath());
-		$body = json_decode($transaction['request']->getBody()->getContents(), true);
-		$this->assertEquals('token', $body['recurring_token']);
-	}
-	
-	public function testDeleteRecurringToken() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->deleteRecurringToken($this->purchase_id);
-		$transaction = $container[0];
-		
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/delete_recurring_token", $transaction['request']->getUri()->getPath());
-	}
-	
-	public function testVerify() {
-		$content = '{"id": "", "due": 1642060235, "type": "purchase", "client": {"cc": [], "bcc": [], "city": "", "email": "", "phone": "", "country": "", "zip_code": "", "bank_code": "", "full_name": "", "brand_name": "", "legal_name": "", "tax_number": "", "client_type": null, "bank_account": "", "personal_code": "", "shipping_city": "", "street_address": "", "shipping_country": "", "shipping_zip_code": "", "registration_number": "", "shipping_street_address": ""}, "issued": "", "status": "created", "is_test": true, "payment": null, "product": "purchases", "user_id": null, "brand_id": "", "order_id": null, "platform": "api", "purchase": {"debt": 0, "notes": "", "total": 100, "currency": "EUR", "language": "en", "products": [{"name": "test", "price": 100, "category": "", "discount": 0, "quantity": "1.0000", "tax_percent": "0.00"}], "timezone": "UTC", "due_strict": false, "email_message": "", "total_override": null, "shipping_options": [], "subtotal_override": null, "total_tax_override": null, "payment_method_details": {}, "request_client_details": [], "total_discount_override": null}, "client_id": null, "reference": "", "viewed_on": null, "company_id": "", "created_on": 1642056635, "event_type": "purchase.created", "updated_on": 1642056635, "invoice_url": null, "checkout_url": "", "send_receipt": false, "skip_capture": false, "creator_agent": "", "issuer_details": {"website": "", "brand_name": "", "legal_city": "", "legal_name": "", "tax_number": "", "bank_accounts": [{"bank_code": "", "bank_account": ""}], "legal_country": "", "legal_zip_code": "", "registration_number": "", "legal_street_address": ""}, "marked_as_paid": false, "status_history": [{"status": "created", "timestamp": 1642056635}], "cancel_redirect": "", "created_from_ip": "", "direct_post_url": null, "force_recurring": false, "recurring_token": null, "failure_redirect": "", "success_callback": "", "success_redirect": "", "transaction_data": {"flow": "payform", "extra": {}, "country": "", "attempts": [], "payment_method": ""}, "refundable_amount": 0, "is_recurring_token": false, "billing_template_id": null, "currency_conversion": null, "reference_generated": "", "refund_availability": "none", "payment_method_whitelist": null}';
-		$signature = 'dHgVBR7qLldrgjMAM0exDnDIBsUU0ZpQC4lkPhAjmjZjkFlRoIYcaC4fR03avykxujZwakM1mGjvInFvCHE8zrrUemeJhHSHN+8n54zecQQ0U84JhdDufr0bSXvSduaqLW1cbBEOHKXm4UCVkMp3bRKzPGEYLM0L6PYd00x3yY53gDeOm05HWlXb5UG8hpKHJPhhr5S58r+hStlM0yAI7tkeTTy6neIin7WKS8imeiGGRh6n46mXEtIcwMzmOaRmQ7me3GAxvD8gDEPY6JV6r3eQZpTF7iX/rU0pod0P35XTvQ3pO2HMBCeRm5zfFCva9JGEVvtiJ1ZDZO/4/UfPEQ==';
-		$publicKey = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEArzedRaG/aa191+f3/Syf\nye4lbwaVDngwBpsV/JidZ3T/27oEAPtwZ3oqhmhsBQcVB/f94ecFdj49NTG1DZZN\nfkWjSZEViL22oEGBryK2MjkUrW30kY1Yh0vCa/e0nIG/+9b1TLfzHIwjm54hw1R/\nRi/m/tf1nLMEm06ogDNV/AUyg6uyNLqp21NxKP7+xV6yfPkfX1s+qSjciyCPzO6r\n+TsG3GTqopG1FSaWx+R0+bmsOEmV5YQKMUlLKlf0wJUD7mjsNioFomEp5QBpASbE\nLfNDO13L5FiUgLtWcz+ZazCZmNUdhstLvrEVt8NhvPWBy96YWm4GfXx7xr8F11yH\npQIDAQAB\n-----END PUBLIC KEY-----";
-		
-		$this->assertTrue(\Chip\ChipApi::verify($content, $signature, $publicKey));
-	}
-	
-	public function testMarkAsPaid() {
-		$container = [];
-		$history = Middleware::history($container);
-		$api = $this->getMockApi(new MockHandler([
-			new Response(200, [], '{}')
-		]), $history);
-		$api->markAsPaid($this->purchase_id);
-		$transaction = $container[0];
-
-		$this->assertEquals('POST', $transaction['request']->getMethod());
-		$this->assertStringContainsString("purchases/$this->purchase_id/mark_as_paid/", $transaction['request']->getUri()->getPath());
-	}
-	
-	protected function getMockApi($mock, $history) {
-		$env = parse_ini_file('.env');
-		$handlerStack = HandlerStack::create($mock);
-		$handlerStack->push($history);
-		return new \Chip\ChipApi($env["BRAND_ID"], $env["API_KEY"], 'https://gate.chip-in.asia/api/v1/', [
-			'handler' => $handlerStack
-		]);
-	}
-
-}
\ No newline at end of file
+    public function testRefundWithoutAmount(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->refund('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/refund', $transaction['request']->getUri()->getPath());
+        $this->assertEmpty($transaction['request']->getBody()->getContents());
+    }
+
+    public function testRefundWithAmount(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->refund('123', 100);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/refund', $transaction['request']->getUri()->getPath());
+        $body = json_decode($transaction['request']->getBody()->getContents(), true);
+        $this->assertEquals(100, $body['amount']);
+    }
+
+    public function testPaymentMethods(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->paymentMethods->list('MYR');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('payment_methods/', $transaction['request']->getUri()->getPath());
+        $body = json_decode($transaction['request']->getBody()->getContents(), true);
+        $this->assertStringContainsString('currency=MYR', $transaction['request']->getUri()->getQuery());
+    }
+
+    public function testCreatePurchase(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->create(new \Chip\Model\Purchase());
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetPurchase(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->get('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testCancelPurchase(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->cancel('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/cancel', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testRelasePurchase(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->release('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/release', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testCaptureWithoutAmount(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->capture('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/capture', $transaction['request']->getUri()->getPath());
+        $this->assertEmpty($transaction['request']->getBody()->getContents());
+    }
+
+    public function testCaptureWithAmount(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->capture('123', 100);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/capture', $transaction['request']->getUri()->getPath());
+        $body = json_decode($transaction['request']->getBody()->getContents(), true);
+        $this->assertEquals(100, $body['amount']);
+    }
+
+    public function testChargePurchase(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->charge('123', 'token');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/charge', $transaction['request']->getUri()->getPath());
+        $body = json_decode($transaction['request']->getBody()->getContents(), true);
+        $this->assertEquals('token', $body['recurring_token']);
+    }
+
+    public function testDeleteRecurringToken(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->deleteRecurringToken('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/delete_recurring_token', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testVerify(): void
+    {
+        $content = '{"id": "", "due": 1642060235, "type": "purchase", "client": {"cc": [], "bcc": [], "city": "", "email": "", "phone": "", "country": "", "zip_code": "", "bank_code": "", "full_name": "", "brand_name": "", "legal_name": "", "tax_number": "", "client_type": null, "bank_account": "", "personal_code": "", "shipping_city": "", "street_address": "", "shipping_country": "", "shipping_zip_code": "", "registration_number": "", "shipping_street_address": ""}, "issued": "", "status": "created", "is_test": true, "payment": null, "product": "purchases", "user_id": null, "brand_id": "", "order_id": null, "platform": "api", "purchase": {"debt": 0, "notes": "", "total": 100, "currency": "EUR", "language": "en", "products": [{"name": "test", "price": 100, "category": "", "discount": 0, "quantity": "1.0000", "tax_percent": "0.00"}], "timezone": "UTC", "due_strict": false, "email_message": "", "total_override": null, "shipping_options": [], "subtotal_override": null, "total_tax_override": null, "payment_method_details": {}, "request_client_details": [], "total_discount_override": null}, "client_id": null, "reference": "", "viewed_on": null, "company_id": "", "created_on": 1642056635, "event_type": "purchase.created", "updated_on": 1642056635, "invoice_url": null, "checkout_url": "", "send_receipt": false, "skip_capture": false, "creator_agent": "", "issuer_details": {"website": "", "brand_name": "", "legal_city": "", "legal_name": "", "tax_number": "", "bank_accounts": [{"bank_code": "", "bank_account": ""}], "legal_country": "", "legal_zip_code": "", "registration_number": "", "legal_street_address": ""}, "marked_as_paid": false, "status_history": [{"status": "created", "timestamp": 1642056635}], "cancel_redirect": "", "created_from_ip": "", "direct_post_url": null, "force_recurring": false, "recurring_token": null, "failure_redirect": "", "success_callback": "", "success_redirect": "", "transaction_data": {"flow": "payform", "extra": {}, "country": "", "attempts": [], "payment_method": ""}, "refundable_amount": 0, "is_recurring_token": false, "billing_template_id": null, "currency_conversion": null, "reference_generated": "", "refund_availability": "none", "payment_method_whitelist": null}';
+        $signature = 'dHgVBR7qLldrgjMAM0exDnDIBsUU0ZpQC4lkPhAjmjZjkFlRoIYcaC4fR03avykxujZwakM1mGjvInFvCHE8zrrUemeJhHSHN+8n54zecQQ0U84JhdDufr0bSXvSduaqLW1cbBEOHKXm4UCVkMp3bRKzPGEYLM0L6PYd00x3yY53gDeOm05HWlXb5UG8hpKHJPhhr5S58r+hStlM0yAI7tkeTTy6neIin7WKS8imeiGGRh6n46mXEtIcwMzmOaRmQ7me3GAxvD8gDEPY6JV6r3eQZpTF7iX/rU0pod0P35XTvQ3pO2HMBCeRm5zfFCva9JGEVvtiJ1ZDZO/4/UfPEQ==';
+        $publicKey = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEArzedRaG/aa191+f3/Syf\nye4lbwaVDngwBpsV/JidZ3T/27oEAPtwZ3oqhmhsBQcVB/f94ecFdj49NTG1DZZN\nfkWjSZEViL22oEGBryK2MjkUrW30kY1Yh0vCa/e0nIG/+9b1TLfzHIwjm54hw1R/\nRi/m/tf1nLMEm06ogDNV/AUyg6uyNLqp21NxKP7+xV6yfPkfX1s+qSjciyCPzO6r\n+TsG3GTqopG1FSaWx+R0+bmsOEmV5YQKMUlLKlf0wJUD7mjsNioFomEp5QBpASbE\nLfNDO13L5FiUgLtWcz+ZazCZmNUdhstLvrEVt8NhvPWBy96YWm4GfXx7xr8F11yH\npQIDAQAB\n-----END PUBLIC KEY-----";
+
+        $this->assertTrue(\Chip\ChipApi::verify($content, $signature, $publicKey));
+    }
+
+    public function testGetPurchaseMapsResponseToModel(): void
+    {
+        $responseBody = $this->jsonResponse([
+            'id' => 'purchase_123',
+            'status' => 'created',
+            'brand_id' => 'brand_456',
+            'purchase' => [
+                'currency' => 'EUR',
+                'total' => 100,
+                'products' => [
+                    ['name' => 'Test Product', 'price' => 100, 'quantity' => 1],
+                ],
+            ],
+            'client' => [
+                'email' => 'test@example.com',
+            ],
+        ]);
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $responseBody),
+        ]), Middleware::history($container));
+
+        $purchase = $api->purchases->get('purchase_123');
+
+        $this->assertInstanceOf(\Chip\Model\Purchase::class, $purchase);
+        $this->assertEquals('purchase_123', $purchase->id);
+        $this->assertEquals('created', $purchase->status);
+        $this->assertEquals('brand_456', $purchase->brand_id);
+        $this->assertInstanceOf(\Chip\Model\PurchaseDetails::class, $purchase->purchase);
+        $this->assertEquals('EUR', $purchase->purchase->currency);
+        $this->assertEquals(100, $purchase->purchase->total);
+        $this->assertCount(1, $purchase->purchase->products);
+        $this->assertInstanceOf(\Chip\Model\Product::class, $purchase->purchase->products[0]);
+        $this->assertEquals('Test Product', $purchase->purchase->products[0]->name);
+        $this->assertInstanceOf(\Chip\Model\ClientDetails::class, $purchase->client);
+        $this->assertEquals('test@example.com', $purchase->client->email);
+    }
+
+    public function testAuthenticationException(): void
+    {
+        $this->expectException(\Chip\Exception\AuthenticationException::class);
+        $this->expectExceptionMessage('Invalid API key');
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(401, [], $this->jsonResponse(['detail' => 'Invalid API key'])),
+        ]), Middleware::history($container));
+
+        $api->purchases->get('123');
+    }
+
+    public function testNotFoundException(): void
+    {
+        $this->expectException(\Chip\Exception\NotFoundException::class);
+        $this->expectExceptionMessage('Purchase not found');
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(404, [], $this->jsonResponse(['detail' => 'Purchase not found'])),
+        ]), Middleware::history($container));
+
+        $api->purchases->get('123');
+    }
+
+    public function testValidationException(): void
+    {
+        $this->expectException(\Chip\Exception\ValidationException::class);
+        $this->expectExceptionMessage('Validation failed');
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(422, [], $this->jsonResponse(['detail' => 'Validation failed', 'errors' => ['email' => 'Required']])),
+        ]), Middleware::history($container));
+
+        $api->purchases->create(new \Chip\Model\Purchase());
+    }
+
+    public function testServerException(): void
+    {
+        $this->expectException(\Chip\Exception\ServerException::class);
+        $this->expectExceptionMessage('Internal server error');
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(500, [], $this->jsonResponse(['detail' => 'Internal server error'])),
+            new Response(500, [], $this->jsonResponse(['detail' => 'Internal server error'])),
+            new Response(500, [], $this->jsonResponse(['detail' => 'Internal server error'])),
+            new Response(500, [], $this->jsonResponse(['detail' => 'Internal server error'])),
+        ]), Middleware::history($container));
+
+        $api->purchases->get('123');
+    }
+
+    public function testValidationExceptionExposesErrors(): void
+    {
+        try {
+            $container = [];
+            $api = $this->getMockApi(new MockHandler([
+                new Response(422, [], $this->jsonResponse(['detail' => 'Validation failed', 'errors' => ['email' => 'Required', 'amount' => 'Must be positive']])),
+            ]), Middleware::history($container));
+
+            $api->purchases->create(new \Chip\Model\Purchase());
+            $this->fail('Expected ValidationException');
+        } catch (\Chip\Exception\ValidationException $e) {
+            $this->assertEquals(['email' => 'Required', 'amount' => 'Must be positive'], $e->getErrors());
+        }
+    }
+
+    public function testCreateClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $client = new \Chip\Model\ClientDetails();
+        $client->email = 'test@example.com';
+        $api->clients->create($client);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testCreateWebhook(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $webhook = new \Chip\Model\Webhook();
+        $webhook->title = 'Test Webhook';
+        $webhook->callback = 'https://example.com/webhook';
+        $api->webhooks->create($webhook);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('webhooks/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetWebhook(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->webhooks->get('wh_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('webhooks/wh_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testMarkAsPaid(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->markAsPaid('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/mark_as_paid/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testMarkAsPaidWithTimestamp(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->markAsPaid('123', 1642060235);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/mark_as_paid/', $transaction['request']->getUri()->getPath());
+        $body = json_decode($transaction['request']->getBody()->getContents(), true);
+        $this->assertEquals(1642060235, $body['paid_on']);
+    }
+
+    public function testPaymentMethodsMapsResponseToModel(): void
+    {
+        $responseBody = $this->jsonResponse([
+            'available_payment_methods' => ['card', 'fpx'],
+            'by_country' => ['MY' => ['fpx']],
+            'country_names' => ['MY' => 'Malaysia'],
+            'names' => ['card' => 'Credit Card', 'fpx' => 'FPX'],
+            'card_methods' => ['visa', 'mastercard'],
+        ]);
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $responseBody),
+        ]), Middleware::history($container));
+
+        $methods = $api->paymentMethods->list('MYR');
+
+        $this->assertInstanceOf(\Chip\Model\PaymentMethods::class, $methods);
+        $this->assertEquals(['card', 'fpx'], $methods->available_payment_methods);
+        $this->assertEquals(['MY' => ['fpx']], $methods->by_country);
+        $this->assertEquals(['MY' => 'Malaysia'], $methods->country_names);
+        $this->assertEquals(['card' => 'Credit Card', 'fpx' => 'FPX'], $methods->names);
+        $this->assertEquals(['visa', 'mastercard'], $methods->card_methods);
+    }
+
+    public function testWebhookMapsResponseToModel(): void
+    {
+        $responseBody = $this->jsonResponse([
+            'id' => 'wh_123',
+            'title' => 'Test Webhook',
+            'callback' => 'https://example.com/webhook',
+            'public_key' => 'abc123',
+            'all_events' => true,
+            'events' => ['purchase.created', 'purchase.paid'],
+        ]);
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $responseBody),
+        ]), Middleware::history($container));
+
+        $webhook = $api->webhooks->get('wh_123');
+
+        $this->assertInstanceOf(\Chip\Model\Webhook::class, $webhook);
+        $this->assertEquals('wh_123', $webhook->id);
+        $this->assertEquals('Test Webhook', $webhook->title);
+        $this->assertEquals('https://example.com/webhook', $webhook->callback);
+        $this->assertEquals('abc123', $webhook->public_key);
+        $this->assertTrue($webhook->all_events);
+        $this->assertEquals(['purchase.created', 'purchase.paid'], $webhook->events);
+    }
+
+    public function testClientDetailsMapsResponseToModel(): void
+    {
+        $responseBody = $this->jsonResponse([
+            'id' => 'client_123',
+            'email' => 'test@example.com',
+            'phone' => '+60123456789',
+            'full_name' => 'Test User',
+            'country' => 'MY',
+            'city' => 'Kuala Lumpur',
+        ]);
+
+        $container = [];
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $responseBody),
+        ]), Middleware::history($container));
+
+        $client = new \Chip\Model\ClientDetails();
+        $client->email = 'test@example.com';
+        $result = $api->clients->create($client);
+
+        $this->assertInstanceOf(\Chip\Model\ClientDetails::class, $result);
+    }
+
+    public function testLoggerReceivesDebugAndErrorCalls(): void
+    {
+        $logger = $this->createMock(\Psr\Log\LoggerInterface::class);
+        $logger->expects($this->once())
+            ->method('debug')
+            ->with('CHIP API request', $this->arrayHasKey('method'));
+        $logger->expects($this->once())
+            ->method('error')
+            ->with('CHIP API client error', $this->arrayHasKey('status'));
+
+        $handlerStack = HandlerStack::create(new MockHandler([
+            new Response(401, [], $this->jsonResponse(['detail' => 'Unauthorized'])),
+        ]));
+        $api = new \Chip\ChipApi('', '', 'https://gate.chip-in.asia/api/v1/', [
+            'handler' => $handlerStack,
+        ], $logger);
+
+        try {
+            $api->purchases->get('123');
+            $this->fail('Expected AuthenticationException');
+        } catch (\Chip\Exception\AuthenticationException $e) {
+            // expected
+        }
+    }
+
+    public function testTimeoutConfiguration(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $handlerStack = HandlerStack::create(new MockHandler([
+            new Response(200, [], '{}'),
+        ]));
+        $handlerStack->push($history);
+
+        $api = new \Chip\ChipApi('', '', 'https://gate.chip-in.asia/api/v1/', [
+            'handler' => $handlerStack,
+            'timeout' => 60,
+        ]);
+
+        $api->purchases->get('123');
+        $transaction = $container[0];
+
+        $this->assertEquals(60, $transaction['options']['timeout']);
+    }
+
+    public function testInvalidWebhookVerificationReturnsFalse(): void
+    {
+        $content = '{"id": "test"}';
+        $signature = 'invalid_signature';
+        $publicKey = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEArzedRaG/aa191+f3/Syf\nye4lbwaVDngwBpsV/JidZ3T/27oEAPtwZ3oqhmhsBQcVB/f94ecFdj49NTG1DZZN\nfkWjSZEViL22oEGBryK2MjkUrW30kY1Yh0vCa/e0nIG/+9b1TLfzHIwjm54hw1R/\nRi/m/tf1nLMEm06ogDNV/AUyg6uyNLqp21NxKP7+xV6yfPkfX1s+qSjciyCPzO6r\n+TsG3GTqopG1FSaWx+R0+bmsOEmV5YQKMUlLKlf0wJUD7mjsNioFomEp5QBpASbE\nLfNDO13L5FiUgLtWcz+ZazCZmNUdhstLvrEVt8NhvPWBy96YWm4GfXx7xr8F11yH\npQIDAQAB\n-----END PUBLIC KEY-----";
+
+        $this->assertFalse(\Chip\ChipApi::verify($content, $signature, $publicKey));
+    }
+
+    public function testCreateBilling(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $billing = new \Chip\Model\Billing\BillingTemplate();
+        $billing->brand_id = 'brand_123';
+        $api->billing->create($billing);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testCreateBillingTemplate(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $billing = new \Chip\Model\Billing\BillingTemplate();
+        $billing->brand_id = 'brand_123';
+        $api->billing->createTemplate($billing);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetBillingTemplates(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->billing->listTemplates();
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetBillingTemplate(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->billing->getTemplate('bt_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testUpdateBillingTemplate(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $billing = new \Chip\Model\Billing\BillingTemplate();
+        $billing->title = 'Updated';
+        $api->billing->updateTemplate('bt_123', $billing);
+        $transaction = $container[0];
+
+        $this->assertEquals('PUT', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testDeleteBillingTemplate(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->billing->deleteTemplate('bt_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('DELETE', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testSendBillingTemplateInvoice(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $client = new \Chip\Model\Billing\BillingTemplateClient();
+        $client->client_id = 'client_123';
+        $api->billing->sendInvoice('bt_123', $client);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/send_invoice/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testAddBillingTemplateSubscriber(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $client = new \Chip\Model\Billing\BillingTemplateClient();
+        $client->client_id = 'client_123';
+        $api->billing->addSubscriber('bt_123', $client);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/add_subscriber/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetBillingTemplateClients(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->billing->listClients('bt_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/clients/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetBillingTemplateClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->billing->getClient('bt_123', 'bc_456');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/clients/bc_456/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testUpdateBillingTemplateClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $client = new \Chip\Model\Billing\BillingTemplateClient();
+        $client->status = 'active';
+        $api->billing->updateClient('bt_123', 'bc_456', $client);
+        $transaction = $container[0];
+
+        $this->assertEquals('PATCH', $transaction['request']->getMethod());
+        $this->assertStringContainsString('billing_templates/bt_123/clients/bc_456/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetClients(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->clients->list();
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testResendInvoice(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+        $api->purchases->resendInvoice('123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('purchases/123/resend_invoice', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->clients->get('client_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testUpdateClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $client = new \Chip\Model\ClientDetails();
+        $client->email = 'updated@example.com';
+        $api->clients->update('client_123', $client);
+        $transaction = $container[0];
+
+        $this->assertEquals('PUT', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testPartialUpdateClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $client = new \Chip\Model\ClientDetails();
+        $client->email = 'updated@example.com';
+        $api->clients->partialUpdate('client_123', $client);
+        $transaction = $container[0];
+
+        $this->assertEquals('PATCH', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testDeleteClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(204, [], ''),
+        ]), $history);
+
+        $api->clients->delete('client_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('DELETE', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testListRecurringTokens(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->clients->listRecurringTokens('client_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/recurring_tokens/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetRecurringToken(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->clients->getRecurringToken('client_123', 'purchase_456');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/recurring_tokens/purchase_456/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testDeleteRecurringTokenByClient(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(204, [], ''),
+        ]), $history);
+
+        $api->clients->deleteRecurringToken('client_123', 'purchase_456');
+        $transaction = $container[0];
+
+        $this->assertEquals('DELETE', $transaction['request']->getMethod());
+        $this->assertStringContainsString('clients/client_123/recurring_tokens/purchase_456/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testListWebhooks(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->webhooks->list();
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('webhooks/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testUpdateWebhook(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $webhook = new \Chip\Model\Webhook();
+        $webhook->title = 'Updated';
+        $api->webhooks->update('wh_123', $webhook);
+        $transaction = $container[0];
+
+        $this->assertEquals('PUT', $transaction['request']->getMethod());
+        $this->assertStringContainsString('webhooks/wh_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testPartialUpdateWebhook(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $webhook = new \Chip\Model\Webhook();
+        $webhook->title = 'Updated';
+        $api->webhooks->partialUpdate('wh_123', $webhook);
+        $transaction = $container[0];
+
+        $this->assertEquals('PATCH', $transaction['request']->getMethod());
+        $this->assertStringContainsString('webhooks/wh_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetPublicKey(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $this->jsonResponse(['public_key' => 'pk_test'])),
+        ]), $history);
+
+        $key = $api->publicKey->get();
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('public_key/', $transaction['request']->getUri()->getPath());
+        $this->assertEquals('pk_test', $key);
+    }
+
+    public function testGetBalance(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $this->jsonResponse(['MYR' => ['balance' => 100]])),
+        ]), $history);
+
+        $result = $api->account->balance(['currency' => 'MYR']);
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('account/json/balance/', $transaction['request']->getUri()->getPath());
+        $this->assertStringContainsString('currency=MYR', $transaction['request']->getUri()->getQuery());
+        $this->assertEquals(['MYR' => ['balance' => 100]], $result);
+    }
+
+    public function testGetTurnover(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], $this->jsonResponse(['incoming' => ['turnover' => 50], 'outgoing' => ['turnover' => 20]])),
+        ]), $history);
+
+        $result = $api->account->turnover(['currency' => 'MYR', 'from' => 1609459200, 'to' => 1609545600]);
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('account/json/turnover/', $transaction['request']->getUri()->getPath());
+        $query = $transaction['request']->getUri()->getQuery();
+        $this->assertStringContainsString('currency=MYR', $query);
+        $this->assertStringContainsString('from=1609459200', $query);
+        $this->assertStringContainsString('to=1609545600', $query);
+    }
+
+    public function testScheduleStatement(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(201, [], '{}'),
+        ]), $history);
+
+        $statement = new \Chip\Model\CompanyStatement();
+        $statement->format = 'csv';
+        $api->statements->schedule($statement);
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('company_statements/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testListStatements(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->statements->list();
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('company_statements/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testGetStatement(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->statements->get('stmt_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $this->assertStringContainsString('company_statements/stmt_123/', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testCancelStatement(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->statements->cancel('stmt_123');
+        $transaction = $container[0];
+
+        $this->assertEquals('POST', $transaction['request']->getMethod());
+        $this->assertStringContainsString('company_statements/stmt_123/cancel', $transaction['request']->getUri()->getPath());
+    }
+
+    public function testPaymentMethodsWithOptionalParams(): void
+    {
+        $container = [];
+        $history = Middleware::history($container);
+        $api = $this->getMockApi(new MockHandler([
+            new Response(200, [], '{}'),
+        ]), $history);
+
+        $api->paymentMethods->list('MYR', ['country' => 'MY', 'recurring' => true, 'amount' => 500]);
+        $transaction = $container[0];
+
+        $this->assertEquals('GET', $transaction['request']->getMethod());
+        $query = $transaction['request']->getUri()->getQuery();
+        $this->assertStringContainsString('country=MY', $query);
+        $this->assertStringContainsString('recurring=1', $query);
+        $this->assertStringContainsString('amount=500', $query);
+    }
+
+    /**
+     * @param array<string, mixed> $data
+     */
+    protected function jsonResponse(array $data): string
+    {
+        $result = json_encode($data);
+        $this->assertIsString($result);
+
+        return $result;
+    }
+
+    protected function getMockApi(MockHandler $mock, callable $history): \Chip\ChipApi
+    {
+        $handlerStack = HandlerStack::create($mock);
+        $handlerStack->push($history);
+
+        return new \Chip\ChipApi('', '', 'https://gate.chip-in.asia/api/v1/', [
+            'handler' => $handlerStack,
+        ]);
+    }
+}
diff --git a/tests/ExceptionTest.php b/tests/ExceptionTest.php
new file mode 100644
index 0000000..491fcb1
--- /dev/null
+++ b/tests/ExceptionTest.php
@@ -0,0 +1,88 @@
+<?php
+
+declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+final class ExceptionTest extends TestCase
+{
+    public function testChipApiExceptionStoresResponseBody(): void
+    {
+        $body = ['detail' => 'Something went wrong'];
+        $e = new \Chip\Exception\ChipApiException('Server error', 500, $body);
+
+        $this->assertEquals('Server error', $e->getMessage());
+        $this->assertEquals(500, $e->getCode());
+        $this->assertEquals($body, $e->getResponseBody());
+    }
+
+    public function testChipApiExceptionAcceptsNullResponseBody(): void
+    {
+        $e = new \Chip\Exception\ChipApiException('No body');
+
+        $this->assertNull($e->getResponseBody());
+    }
+
+    public function testAuthenticationExceptionExtendsChipApiException(): void
+    {
+        $e = new \Chip\Exception\AuthenticationException('Invalid API key', 401, ['detail' => 'Invalid API key']);
+
+        $this->assertInstanceOf(\Chip\Exception\ChipApiException::class, $e);
+        $this->assertEquals('Invalid API key', $e->getMessage());
+        $this->assertEquals(['detail' => 'Invalid API key'], $e->getResponseBody());
+    }
+
+    public function testNotFoundExceptionExtendsChipApiException(): void
+    {
+        $e = new \Chip\Exception\NotFoundException('Not found', 404);
+
+        $this->assertInstanceOf(\Chip\Exception\ChipApiException::class, $e);
+        $this->assertEquals('Not found', $e->getMessage());
+    }
+
+    public function testValidationExceptionExtractsErrorsFromResponseBody(): void
+    {
+        $body = ['detail' => 'Validation failed', 'errors' => ['email' => 'Required']];
+        $e = new \Chip\Exception\ValidationException('Validation failed', 422, $body);
+
+        $this->assertInstanceOf(\Chip\Exception\ChipApiException::class, $e);
+        $this->assertEquals(['email' => 'Required'], $e->getErrors());
+        $this->assertEquals($body, $e->getResponseBody());
+    }
+
+    public function testValidationExceptionReturnsEmptyErrorsWhenMissing(): void
+    {
+        $e = new \Chip\Exception\ValidationException('Validation failed', 422, ['detail' => 'Bad request']);
+
+        $this->assertEquals([], $e->getErrors());
+    }
+
+    public function testValidationExceptionReturnsEmptyErrorsWhenNullBody(): void
+    {
+        $e = new \Chip\Exception\ValidationException('Validation failed');
+
+        $this->assertEquals([], $e->getErrors());
+    }
+
+    public function testClientExceptionExtendsChipApiException(): void
+    {
+        $e = new \Chip\Exception\ClientException('Bad request', 400, ['detail' => 'Bad request']);
+
+        $this->assertInstanceOf(\Chip\Exception\ChipApiException::class, $e);
+    }
+
+    public function testServerExceptionExtendsChipApiException(): void
+    {
+        $e = new \Chip\Exception\ServerException('Internal server error', 500, ['detail' => 'Internal server error']);
+
+        $this->assertInstanceOf(\Chip\Exception\ChipApiException::class, $e);
+    }
+
+    public function testExceptionPreservesPreviousException(): void
+    {
+        $previous = new \RuntimeException('Network failure');
+        $e = new \Chip\Exception\ServerException('Server error', 500, null, $previous);
+
+        $this->assertSame($previous, $e->getPrevious());
+    }
+}
diff --git a/tests/ModelTest.php b/tests/ModelTest.php
new file mode 100644
index 0000000..1f5660d
--- /dev/null
+++ b/tests/ModelTest.php
@@ -0,0 +1,232 @@
+<?php
+
+declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+final class ModelTest extends TestCase
+{
+    public function testPurchaseSerializesOnlyNonNullValues(): void
+    {
+        $purchase = new \Chip\Model\Purchase();
+        $purchase->id = 'p123';
+        $purchase->status = 'created';
+        $purchase->brand_id = 'brand_456';
+
+        $json = json_encode($purchase);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('p123', $decoded['id']);
+        $this->assertEquals('created', $decoded['status']);
+        $this->assertEquals('brand_456', $decoded['brand_id']);
+        $this->assertArrayNotHasKey('reference', $decoded);
+    }
+
+    public function testPurchaseDetailsSerializesProductsArray(): void
+    {
+        $details = new \Chip\Model\PurchaseDetails();
+        $details->currency = 'USD';
+        $details->total = 500;
+        $details->language = 'en';
+
+        $product = new \Chip\Model\Product();
+        $product->name = 'Widget';
+        $product->price = 500;
+        $product->quantity = '1.0';
+        $details->products = [$product];
+
+        $json = json_encode($details);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('USD', $decoded['currency']);
+        $this->assertEquals(500, $decoded['total']);
+        $this->assertCount(1, $decoded['products']);
+        $this->assertEquals('Widget', $decoded['products'][0]['name']);
+    }
+
+    public function testProductStripsNullValues(): void
+    {
+        $product = new \Chip\Model\Product();
+        $product->name = 'Gadget';
+        $product->price = 100;
+        $product->quantity = '2.0';
+
+        $json = json_encode($product);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertArrayHasKey('name', $decoded);
+        $this->assertArrayHasKey('price', $decoded);
+        $this->assertArrayNotHasKey('discount', $decoded);
+        $this->assertArrayNotHasKey('tax_percent', $decoded);
+    }
+
+    public function testClientDetailsSerializesAndStripsNulls(): void
+    {
+        $client = new \Chip\Model\ClientDetails();
+        $client->email = 'test@example.com';
+        $client->full_name = 'Test User';
+        $client->country = 'MY';
+        $client->city = 'Kuala Lumpur';
+
+        $json = json_encode($client);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('test@example.com', $decoded['email']);
+        $this->assertEquals('Test User', $decoded['full_name']);
+        $this->assertArrayNotHasKey('phone', $decoded);
+        $this->assertArrayNotHasKey('street_address', $decoded);
+    }
+
+    public function testWebhookSerializesAndStripsNulls(): void
+    {
+        $webhook = new \Chip\Model\Webhook();
+        $webhook->id = 'wh_123';
+        $webhook->title = 'Test Webhook';
+        $webhook->callback = 'https://example.com/webhook';
+        $webhook->all_events = true;
+        $webhook->events = ['purchase.created'];
+
+        $json = json_encode($webhook);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('wh_123', $decoded['id']);
+        $this->assertEquals('Test Webhook', $decoded['title']);
+        $this->assertEquals('https://example.com/webhook', $decoded['callback']);
+        $this->assertTrue($decoded['all_events']);
+        $this->assertEquals(['purchase.created'], $decoded['events']);
+        $this->assertArrayNotHasKey('public_key', $decoded);
+    }
+
+    public function testPaymentMethodsSerializesAndStripsNulls(): void
+    {
+        $methods = new \Chip\Model\PaymentMethods();
+        $methods->available_payment_methods = ['card', 'fpx'];
+        $methods->by_country = ['MY' => ['fpx']];
+        $methods->country_names = ['MY' => 'Malaysia'];
+        $methods->names = ['card' => 'Credit Card'];
+        $methods->card_methods = ['visa', 'mastercard'];
+
+        $json = json_encode($methods);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals(['card', 'fpx'], $decoded['available_payment_methods']);
+        $this->assertEquals(['MY' => ['fpx']], $decoded['by_country']);
+        $this->assertArrayNotHasKey('logos', $decoded);
+    }
+
+    public function testBillingTemplateStripsNulls(): void
+    {
+        $template = new \Chip\Model\Billing\BillingTemplate();
+        $template->brand_id = 'brand_123';
+        $template->title = 'Monthly Plan';
+        $template->is_subscription = true;
+
+        $json = json_encode($template);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('brand_123', $decoded['brand_id']);
+        $this->assertEquals('Monthly Plan', $decoded['title']);
+        $this->assertTrue($decoded['is_subscription']);
+        $this->assertArrayNotHasKey('invoice_issued', $decoded);
+    }
+
+    public function testBillingTemplateClientStripsNulls(): void
+    {
+        $client = new \Chip\Model\Billing\BillingTemplateClient();
+        $client->client_id = 'client_123';
+        $client->status = 'active';
+
+        $json = json_encode($client);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('client_123', $decoded['client_id']);
+        $this->assertEquals('active', $decoded['status']);
+        $this->assertArrayNotHasKey('payment_method_whitelist', $decoded);
+    }
+
+    public function testBillingTemplateClientAddSubscriberStripsNulls(): void
+    {
+        $subscriber = new \Chip\Model\Billing\BillingTemplateClientAddSubscriber();
+
+        $json = json_encode($subscriber);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertIsArray($decoded);
+    }
+
+    public function testBillingTemplateClientListStripsNulls(): void
+    {
+        $list = new \Chip\Model\Billing\BillingTemplateClientList();
+        $list->results = [];
+
+        $json = json_encode($list);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        // empty array is filtered out by array_filter
+        $this->assertArrayNotHasKey('results', $decoded);
+        $this->assertArrayNotHasKey('next', $decoded);
+    }
+
+    public function testBillingTemplateListStripsNulls(): void
+    {
+        $list = new \Chip\Model\Billing\BillingTemplateList();
+        $list->results = [];
+
+        $json = json_encode($list);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        // empty array is filtered out by array_filter
+        $this->assertArrayNotHasKey('results', $decoded);
+        $this->assertArrayNotHasKey('previous', $decoded);
+    }
+
+    public function testEmptyModelSerializesToEmptyObject(): void
+    {
+        $purchase = new \Chip\Model\Purchase();
+
+        $json = json_encode($purchase);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertIsArray($decoded);
+        $this->assertEmpty($decoded);
+    }
+
+    public function testNestedModelSerialization(): void
+    {
+        $purchase = new \Chip\Model\Purchase();
+        $purchase->brand_id = 'brand_123';
+
+        $details = new \Chip\Model\PurchaseDetails();
+        $details->currency = 'EUR';
+        $details->total = 100;
+
+        $product = new \Chip\Model\Product();
+        $product->name = 'Test';
+        $product->price = 100;
+        $product->quantity = '1.0';
+        $details->products = [$product];
+
+        $purchase->purchase = $details;
+
+        $json = json_encode($purchase);
+        $this->assertIsString($json);
+        $decoded = json_decode($json, true);
+
+        $this->assertEquals('brand_123', $decoded['brand_id']);
+        $this->assertEquals('EUR', $decoded['purchase']['currency']);
+        $this->assertCount(1, $decoded['purchase']['products']);
+        $this->assertEquals('Test', $decoded['purchase']['products'][0]['name']);
+    }
+}
diff --git a/tests/PurchaseBuilderTest.php b/tests/PurchaseBuilderTest.php
new file mode 100644
index 0000000..dcdc8fe
--- /dev/null
+++ b/tests/PurchaseBuilderTest.php
@@ -0,0 +1,51 @@
+<?php
+
+use PHPUnit\Framework\TestCase;
+
+final class PurchaseBuilderTest extends TestCase
+{
+    public function testBuildsPurchaseWithFluentApi(): void
+    {
+        $purchase = \Chip\Builder\PurchaseBuilder::create()
+            ->brandId('brand_123')
+            ->currency('USD')
+            ->language('en')
+            ->successRedirect('https://example.com/success')
+            ->failureRedirect('https://example.com/failure')
+            ->successCallback('https://example.com/callback')
+            ->clientEmail('test@example.com')
+            ->clientFullName('Test User')
+            ->addProduct('Widget', 5000, 2)
+            ->addProduct('Gadget', 3000)
+            ->build();
+
+        $this->assertInstanceOf(\Chip\Model\Purchase::class, $purchase);
+        $this->assertEquals('brand_123', $purchase->brand_id);
+        $this->assertEquals('USD', $purchase->purchase->currency);
+        $this->assertEquals('en', $purchase->purchase->language);
+        $this->assertEquals('https://example.com/success', $purchase->success_redirect);
+        $this->assertEquals('https://example.com/failure', $purchase->failure_redirect);
+        $this->assertEquals('https://example.com/callback', $purchase->success_callback);
+
+        $this->assertInstanceOf(\Chip\Model\ClientDetails::class, $purchase->client);
+        $this->assertEquals('test@example.com', $purchase->client->email);
+        $this->assertEquals('Test User', $purchase->client->full_name);
+
+        $this->assertCount(2, $purchase->purchase->products);
+        $this->assertEquals('Widget', $purchase->purchase->products[0]->name);
+        $this->assertEquals(5000, $purchase->purchase->products[0]->price);
+        $this->assertEquals(2.0, $purchase->purchase->products[0]->quantity);
+        $this->assertEquals('Gadget', $purchase->purchase->products[1]->name);
+        $this->assertEquals(3000, $purchase->purchase->products[1]->price);
+        $this->assertEquals(1.0, $purchase->purchase->products[1]->quantity);
+    }
+
+    public function testProductsArrayDefaultsToEmpty(): void
+    {
+        $purchase = \Chip\Builder\PurchaseBuilder::create()
+            ->brandId('brand_123')
+            ->build();
+
+        $this->assertEmpty($purchase->purchase->products);
+    }
+}