Chart API

The ChartQuery Chart API renders a Chart.js configuration as an image, or generates a chart from a plain-English prompt with AI.

• Chart Render API — Render a Chart.js image via GET.
• AI Chart API — Describe a chart in plain English via GET and get a rendered image back.

Use it for charts in emails, PDF reports, Slack bots, dashboards and AI assistants.

Endpoint	Request	Credits
Chart Render API	GET /v1/chart	5
AI Chart API	GET /v1/chart/ai	10

Table of contents

• How it works
• Chart Render API
• AI Chart API
• Code examples in other languages
• Use cases
• Why ChartQuery?
• FAQ
• Related repositories
• Support

How it works

1. Create a ChartQuery account and copy your API key from the dashboard.
2. Call https://api.chartquery.com with the header x-api-key: YOUR_API_KEY.
3. Use the result in your app — no infrastructure to run.

export CHARTQUERY_API_KEY="your-api-key"
pip install requests        # Python
# TypeScript: Node.js 18+ (native fetch), run with `npx tsx file.ts`

Chart Render API

Render a Chart.js image via GET. Pass the full chart object as URL-encoded JSON in query. Prefer format png for ChatGPT. POST sends the same object as a JSON body, not query.

GET https://api.chartquery.com/v1/chart · 5 credits per request · API reference

Request parameters

Parameter	In	Type	Required	Description
query	query	string	✅	Full chart config as URL-encoded JSON. Pass ?version= or ?v= separately to pin the chart version.
version	query	string	—	Chart.js version to use. Alias: ?v=. Only v4.x is supported. Defaults to the installed version (4.5.1). Example: "4", "4.5", "4.5.1". The installed version is always returned in the X-ChartJS-Version response header.
share	query	boolean	—	If true, persist the result and return share URLs instead of an image. Leave false to get the image.

Python example

import os

import requests

API_KEY = os.environ["CHARTQUERY_API_KEY"]
HEADERS = {"x-api-key": API_KEY}

response = requests.get(
    "https://api.chartquery.com/v1/chart",
    headers=HEADERS,
    params={
        "query": "{\"type\":\"bar\",\"title\":\"Monthly Sales\",\"legend\":\"bottom\",\"width\":1200,\"height\":600,\"device_pixel_ratio\":1,\"data\":{\"labels\":[\"Jan\",\"Feb\",\"Mar\",\"Apr\",\"May\",\"Jun\"],\"datasets\":[{\"label\":\"2025\",\"data\":[42,58,37,65,49,72],\"backgroundColor\":\"rgba(99,102,241,0.85)\"},{\"label\":\"2026\",\"data\":[51,67,44,71,58,85],\"backgroundColor\":\"rgba(249,115,22,0.85)\"}]},\"scales\":{\"y\":{\"beginAtZero\":true}}}",
    },
    timeout=120,
)
response.raise_for_status()

with open("chart.png", "wb") as f:
    f.write(response.content)
print("Saved chart.png", len(response.content), "bytes")

TypeScript example

import { writeFile } from "node:fs/promises";

const headers = { "x-api-key": process.env.CHARTQUERY_API_KEY!, "Content-Type": "application/json" };

const params = new URLSearchParams({
  "query": "{\"type\":\"bar\",\"title\":\"Monthly Sales\",\"legend\":\"bottom\",\"width\":1200,\"height\":600,\"device_pixel_ratio\":1,\"data\":{\"labels\":[\"Jan\",\"Feb\",\"Mar\",\"Apr\",\"May\",\"Jun\"],\"datasets\":[{\"label\":\"2025\",\"data\":[42,58,37,65,49,72],\"backgroundColor\":\"rgba(99,102,241,0.85)\"},{\"label\":\"2026\",\"data\":[51,67,44,71,58,85],\"backgroundColor\":\"rgba(249,115,22,0.85)\"}]},\"scales\":{\"y\":{\"beginAtZero\":true}}}",
});

const response = await fetch(`https://api.chartquery.com/v1/chart?${params}`, { headers });
if (!response.ok) throw new Error(`HTTP ${response.status}: ${await response.text()}`);

await writeFile("chart.png", Buffer.from(await response.arrayBuffer()));
console.log("Saved chart.png");

Output

The response body is the generated file (saved as chart.png in every example). Error responses are JSON with an explanatory message.

AI Chart API

Describe a chart in plain English via GET and get a rendered image back. Powered by AI.

GET https://api.chartquery.com/v1/chart/ai · 10 credits per request · API reference

Request parameters

Parameter	In	Type	Required	Description
prompt	query	string	✅	Describe your chart in plain English (max 1000 chars). Be specific: mention chart type, data topic, colors, style.
raw_data	query	string	—	Raw data for the chart. URL-encoded string, CSV, or JSON. AI will parse and structure it.
title	query	string	—	Override the chart title generated by AI.
subtitle	query	string	—	Override the chart subtitle.
legend	query	string (top, bottom, left, right, chartArea, false)	—	Legend position or visibility. Use "false" to hide.
format	query	string (png, svg)	—	Output format. Default: "png".
width	query	number	—	Image width in pixels (50–4000). Default: 1200.
height	query	number	—	Image height in pixels (50–4000). Default: 600.
background	query	string	—	Background color as a hex value. Default: #ffffff.
device_pixel_ratio	query	number	—	Device pixel ratio for the rendered image. Default: 1.
share	query	boolean (false, true)	—	Set share=true to persist the config and receive JSON instead of an image: { id, render_url, view_url, embed_url, expires_in }. Free plan: 3-day expiry with watermark. Paid plan: 6-month expiry, no branding.

Python example

import os

import requests

API_KEY = os.environ["CHARTQUERY_API_KEY"]
HEADERS = {"x-api-key": API_KEY}

response = requests.get(
    "https://api.chartquery.com/v1/chart/ai",
    headers=HEADERS,
    params={
        "prompt": "Bar chart of monthly sales from January to June, indigo bars, clean style",
        "format": "png",
    },
    timeout=120,
)
response.raise_for_status()

with open("ai-chart.png", "wb") as f:
    f.write(response.content)
print("Saved ai-chart.png", len(response.content), "bytes")

TypeScript example

import { writeFile } from "node:fs/promises";

const headers = { "x-api-key": process.env.CHARTQUERY_API_KEY!, "Content-Type": "application/json" };

const params = new URLSearchParams({
  "prompt": "Bar chart of monthly sales from January to June, indigo bars, clean style",
  "format": "png",
});

const response = await fetch(`https://api.chartquery.com/v1/chart/ai?${params}`, { headers });
if (!response.ok) throw new Error(`HTTP ${response.status}: ${await response.text()}`);

await writeFile("ai-chart.png", Buffer.from(await response.arrayBuffer()));
console.log("Saved ai-chart.png");

Output

The response body is the generated file (saved as ai-chart.png in every example). Error responses are JSON with an explanatory message.

Code examples in other languages

Ready-to-run examples live in examples/; each reads your key from CHARTQUERY_API_KEY.

Language	chart	chart-ai
cURL (Bash)	chart.sh	chart_ai.sh
PHP	chart.php	chart_ai.php
C#	Chart.cs	ChartAi.cs
Go	chart.go	chart_ai.go
Java	ChartExample.java	ChartAiExample.java
Ruby	chart.rb	chart_ai.rb
Node.js	chart.mjs	chart_ai.mjs

Use cases

• Email & PDF reports — Embed charts where JavaScript can't run.
• Chatbots & AI agents — Return charts as images from Slack, Discord or ChatGPT tools.
• Automated reporting — Generate weekly KPI charts from your data pipeline.

Why ChartQuery?

• Images in one request — the response body is the PNG/SVG/PDF, ready for emails, PDFs, dashboards, Slack or <img> tags.
• Charts, diagrams, QR codes, barcodes, labels — Chart.js configs, 28 diagram languages (Mermaid, Graphviz, PlantUML, D2…), 25+ barcode formats.
• AI generation — describe a chart or diagram in plain English and get the rendered image.
• No rendering infrastructure — no headless browser, fonts or libraries to maintain.
• Copy-paste examples — Python and TypeScript in each README, 7 more languages in examples/.

FAQ

How do I authenticate?

Create an account on ChartQuery, copy your API key and send it in the x-api-key header of every request to https://api.chartquery.com.

How much does a request cost?

Credits per call: /v1/chart 5, /v1/chart/ai 10. See ChartQuery pricing.

What does the API return?

The response body is the file itself (image or document). Save it directly to disk or stream it to your storage — every example in this repository writes the file locally.

Which languages are supported?

Any language that can make an HTTP request. This README shows Python and TypeScript; the examples/ folder contains cURL, PHP, C#, Go, Java, Ruby and Node.js.

Related repositories

• Diagram API
• QR Code API
• Barcode API
• Thermal Label API
• All ChartQuery repositories

Support

• 💬 Join the Discord to ask questions and share what you build.
• 📚 Read the API reference.
• 🔑 Get your API key.

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_{Built by ChartQuery. Examples are released under the MIT license.}