diff --git a/README.md b/README.md
index 865ddb7..2d76f1c 100644
--- a/README.md
+++ b/README.md
@@ -21,13 +21,13 @@ Use them in the browser, clone them locally, or extend them as building blocks i
 | 🔍 Pretty JSON  | Prettify and explore JSON in a tree view.           | JSON              | [Get it here](./pretty-json.html)     |
 | 📝 ReadMark     | Markdown editor with live preview and templates.    | Markdown          | [Get it here](./markdown-editor.html) |
 | 📡 JWT Decoder  | Decode and inspect JWT tokens with details.         | Encoder/Decoder   | [Get it here](./jwt-decoder.html)     |
+| 📝 Regex Tester | Test, validate, and explore your regular expressions.| Regex             | [Get it here](./Regex/regex-tester.html) |
 
 
 ## 🛣️ Planned Tools
 
 We're just getting started! Some ideas in the pipeline:
 
-- 📝 Regex Tester (pattern + test string)
 - 🔄 Text Case Converter (camelCase, snake_case, Title Case)
 - 🧮 UUID / Hash Generator
 - ⚖️ Text Diff Viewer
diff --git a/Regex/regex-tester.html b/Regex/regex-tester.html
new file mode 100644
index 0000000..61b43a8
--- /dev/null
+++ b/Regex/regex-tester.html
@@ -0,0 +1,363 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Regex Tester | Tiny Dev Tools</title>
+    <style>
+        :root {
+            --primary-color: #3498db;
+            --secondary-color: #2c3e50;
+            --accent-color: #e74c3c;
+            --light-color: #ecf0f1;
+            --dark-color: #34495e;
+            --success-color: #2ecc71;
+            --warning-color: #f39c12;
+        }
+
+        * {
+            box-sizing: border-box;
+            margin: 0;
+            padding: 0;
+            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
+        }
+
+        body {
+            background-color: #f5f5f5;
+            color: var(--dark-color);
+            line-height: 1.6;
+            padding: 20px;
+        }
+
+        .container {
+            max-width: 1000px;
+            margin: 0 auto;
+            background-color: white;
+            border-radius: 8px;
+            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
+            padding: 20px;
+        }
+
+        header {
+            margin-bottom: 20px;
+            text-align: center;
+        }
+
+        h1 {
+            color: var(--secondary-color);
+            margin-bottom: 10px;
+        }
+
+        p {
+            color: var(--dark-color);
+        }
+
+        .input-section {
+            display: flex;
+            flex-direction: column;
+            gap: 15px;
+            background-color: var(--light-color);
+            padding: 20px;
+            border-radius: 6px;
+            margin-bottom: 20px;
+        }
+
+        .input-group {
+            display: flex;
+            flex-direction: column;
+            gap: 5px;
+        }
+
+        label {
+            font-weight: bold;
+            font-size: 14px;
+            color: var(--secondary-color);
+        }
+
+        .regex-wrapper {
+            display: flex;
+            align-items: stretch;
+            background: white;
+            border: 1px solid #ddd;
+            border-radius: 4px;
+            overflow: hidden;
+        }
+
+        .regex-prefix, .regex-suffix {
+            background-color: #f8f9fa;
+            color: var(--dark-color);
+            padding: 10px 15px;
+            font-family: monospace;
+            border-right: 1px solid #ddd;
+            display: flex;
+            align-items: center;
+            font-size: 16px;
+        }
+        
+        .regex-suffix {
+            border-right: none;
+            border-left: 1px solid #ddd;
+        }
+
+        input[type="text"] {
+            flex: 1;
+            padding: 10px;
+            border: none;
+            font-family: monospace;
+            font-size: 14px;
+            outline: none;
+        }
+
+        .flags-input {
+            width: 60px !important;
+            text-align: center;
+            background-color: #f8f9fa;
+            border-left: 1px solid #ddd;
+        }
+
+        textarea {
+            padding: 15px;
+            border: 1px solid #ddd;
+            border-radius: 4px;
+            font-family: monospace;
+            font-size: 14px;
+            resize: vertical;
+            min-height: 120px;
+            outline: none;
+        }
+
+        textarea:focus, .regex-wrapper:focus-within {
+            border-color: var(--primary-color);
+            box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
+        }
+
+        .error {
+            background-color: #ffecec;
+            color: var(--accent-color);
+            border: 1px solid #f5aca6;
+            padding: 10px 15px;
+            border-radius: 4px;
+            font-size: 14px;
+            display: none;
+            margin-top: 5px;
+        }
+
+        .error.visible {
+            display: block;
+        }
+
+        .results-container {
+            margin-top: 20px;
+        }
+
+        .results-header {
+            display: flex;
+            justify-content: space-between;
+            align-items: center;
+            margin-bottom: 15px;
+        }
+
+        h3 {
+            color: var(--secondary-color);
+        }
+
+        .match-count {
+            background-color: var(--light-color);
+            color: var(--secondary-color);
+            padding: 5px 12px;
+            border-radius: 12px;
+            font-size: 14px;
+            font-weight: bold;
+        }
+        
+        .match-count.has-matches {
+            background-color: #e9ffd9;
+            color: var(--success-color);
+            border: 1px solid #a6ca8a;
+        }
+
+        .results-content {
+            background-color: #f8f8f8;
+            padding: 15px;
+            border-radius: 4px;
+            border: 1px solid #ddd;
+            white-space: pre-wrap;
+            font-family: monospace;
+            min-height: 150px;
+            font-size: 14px;
+            color: var(--dark-color);
+        }
+
+        .match {
+            background-color: #d4edda;
+            color: #155724;
+            border-radius: 3px;
+            padding: 0 2px;
+            border-bottom: 2px solid var(--success-color);
+        }
+
+        .empty-state {
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            height: 100%;
+            color: #7f8c8d;
+            font-style: italic;
+            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
+        }
+
+    </style>
+</head>
+<body>
+
+    <div class="container">
+        <header>
+            <h1>Regex Tester</h1>
+            <p>Test, validate, and explore your regular expressions instantly</p>
+        </header>
+
+        <div class="input-section">
+            <div class="input-group">
+                <label for="regex">Regular Expression</label>
+                <div class="regex-wrapper">
+                    <div class="regex-prefix">/</div>
+                    <input type="text" id="regex" placeholder="[a-zA-Z0-9]+" value="[a-zA-Z0-9]+">
+                    <div class="regex-suffix">/</div>
+                    <input type="text" id="flags" class="flags-input" placeholder="g" value="g" title="Regex Flags (e.g., g, i, m)">
+                </div>
+                <div id="regex-error" class="error">Invalid regular expression</div>
+            </div>
+
+            <div class="input-group">
+                <label for="test-string">Test String</label>
+                <textarea id="test-string" placeholder="Enter text to test your regex against...">Welcome to Tiny Dev Tools Regex Tester!
+This tool helps you extract 123 numbers, emails like user@example.com, and more.
+It's built in 2026 and aims to be 100% awesome.</textarea>
+            </div>
+        </div>
+
+        <div class="results-container">
+            <div class="results-header">
+                <h3>Match Results</h3>
+                <span class="match-count" id="match-count">0 Matches</span>
+            </div>
+            <div class="results-content" id="results">
+                <!-- Matches will be highlighted here -->
+            </div>
+        </div>
+    </div>
+
+    <script>
+        const regexInput = document.getElementById('regex');
+        const flagsInput = document.getElementById('flags');
+        const testStringInput = document.getElementById('test-string');
+        const resultsDiv = document.getElementById('results');
+        const matchCountSpan = document.getElementById('match-count');
+        const errorMsg = document.getElementById('regex-error');
+
+        function updateResults() {
+            const regexStr = regexInput.value;
+            let flagsStr = flagsInput.value;
+            const testStr = testStringInput.value;
+
+            errorMsg.classList.remove('visible');
+
+            if (!regexStr) {
+                resultsDiv.innerHTML = '<div class="empty-state">Enter a regular expression to see matches.</div>';
+                matchCountSpan.textContent = '0 Matches';
+                matchCountSpan.classList.remove('has-matches');
+                return;
+            }
+
+            if (!testStr) {
+                resultsDiv.innerHTML = '<div class="empty-state">Enter a test string to test against.</div>';
+                matchCountSpan.textContent = '0 Matches';
+                matchCountSpan.classList.remove('has-matches');
+                return;
+            }
+
+            try {
+                // Remove invalid flags
+                const validFlags = ['g', 'i', 'm', 's', 'u', 'y'];
+                let cleanFlags = '';
+                for (let char of flagsStr) {
+                    if (validFlags.includes(char) && !cleanFlags.includes(char)) {
+                        cleanFlags += char;
+                    }
+                }
+                
+                const regex = new RegExp(regexStr, cleanFlags);
+                
+                let highlightedHtml = '';
+                let matchCount = 0;
+                
+                if (regex.global) {
+                    let lastIndex = 0;
+                    let match;
+                    
+                    regex.lastIndex = 0;
+
+                    const matches = [];
+                    while ((match = regex.exec(testStr)) !== null) {
+                        matches.push(match);
+                        if (match.index === regex.lastIndex) {
+                            regex.lastIndex++;
+                        }
+                    }
+
+                    matchCount = matches.length;
+
+                    for (const m of matches) {
+                        highlightedHtml += escapeHtml(testStr.slice(lastIndex, m.index));
+                        highlightedHtml += `<span class="match">${escapeHtml(m[0])}</span>`;
+                        lastIndex = m.index + m[0].length;
+                    }
+                    highlightedHtml += escapeHtml(testStr.slice(lastIndex));
+
+                } else {
+                    const match = regex.exec(testStr);
+                    if (match) {
+                        matchCount = 1;
+                        highlightedHtml += escapeHtml(testStr.slice(0, match.index));
+                        highlightedHtml += `<span class="match">${escapeHtml(match[0])}</span>`;
+                        highlightedHtml += escapeHtml(testStr.slice(match.index + match[0].length));
+                    } else {
+                        highlightedHtml = escapeHtml(testStr);
+                    }
+                }
+
+                resultsDiv.innerHTML = highlightedHtml || escapeHtml(testStr);
+                matchCountSpan.textContent = `${matchCount} Match${matchCount !== 1 ? 'es' : ''}`;
+                
+                if (matchCount > 0) {
+                    matchCountSpan.classList.add('has-matches');
+                } else {
+                    matchCountSpan.classList.remove('has-matches');
+                }
+
+            } catch (e) {
+                errorMsg.textContent = e.message;
+                errorMsg.classList.add('visible');
+                resultsDiv.innerHTML = escapeHtml(testStr);
+                matchCountSpan.textContent = 'Error';
+                matchCountSpan.classList.remove('has-matches');
+            }
+        }
+
+        function escapeHtml(unsafe) {
+            return unsafe
+                 .replace(/&/g, "&amp;")
+                 .replace(/</g, "&lt;")
+                 .replace(/>/g, "&gt;")
+                 .replace(/"/g, "&quot;")
+                 .replace(/'/g, "&#039;");
+        }
+
+        regexInput.addEventListener('input', updateResults);
+        flagsInput.addEventListener('input', updateResults);
+        testStringInput.addEventListener('input', updateResults);
+
+        updateResults();
+    </script>
+</body>
+</html>
