JS Beautifier
Beautify minified or messy JavaScript with proper indentation, line breaks, and spacing. 📖 Make any JS readable again
🔍 What Is a JS Beautifier?
A JS Beautifier (also called a JavaScript formatter or pretty printer) takes minified, compressed, or poorly indented JavaScript and rewrites it with consistent indentation, line breaks, and spacing — so the code becomes readable again. Minification strips all the human-friendly whitespace to shrink file size, which is great for production but terrible for debugging. A beautifier restores the structure without changing behaviour.
◆ This tool processes everything entirely in your browser — no code is ever uploaded to any server. Your JavaScript stays private.
✨ Key Features
Configurable Indentation
Choose 2, 4, 6, or 8 spaces — or tabs — for indentation width. The output matches your preferred style.
Brace Style Options
Pick between collapse (braces on the same line) and expand (braces on their own line, Allman style).
Safe Token-Based Formatting
Built on a real JavaScript tokenizer. Strings, regex literals, template literals, and comments are treated as atomic tokens — never altered.
Live Size & Line Report
See original size, output size, total lines, and the indentation width used. Confirm the formatter did what you expected.
Comment Preservation
All comments — line and block — are preserved and re-indented to match the surrounding code.
Copy & Download
Copy the beautified code to your clipboard or download it as a .js file ready to use.
💡 Why Use This JS Beautifier?
100% Private & Secure
All processing happens in your browser. Your JavaScript never leaves your device — no uploads, no servers, no tracking.
Works Everywhere
Use it on your phone, tablet, laptop, or desktop. The interface adapts to any screen size.
Instant Results
Beautification happens in milliseconds. No page reloads, no waiting — just paste and click Beautify.
Completely Free
No sign-up, no hidden fees, no usage limits. Use it as much as you need.
Accessible & Keyboard-Friendly
Full keyboard support, visible focus states, and semantic HTML ensure everyone can use the tool effectively.
Works Offline
Once the page loads, the tool works entirely offline — no internet connection required.
📖 How to Use the JS Beautifier
- Paste your JavaScript into the input area. You can also click Sample to load an example.
- Choose your style — pick indent width (2–8 spaces or tabs), brace style (collapse or expand), and toggle spacing options.
- Click Beautify to generate the formatted output. The result appears instantly.
- Review the stats — see the original size, output size, total lines, and indent setting used.
- Copy or Download — click Copy for the clipboard, or Download to save as a
.jsfile. - Clear everything to start fresh, or press Ctrl+Enter to beautify instantly.
🎯 Practical Use Cases
Debugging Minified Code
When a production error points to a minified file, beautify it to read the actual logic and trace the bug.
Learning from Library Code
Beautify minified third-party scripts to understand how a library works internally.
Cleaning Up Legacy Code
Reformat poorly indented legacy JavaScript into a consistent, readable style.
Code Reviews & Documentation
Format code before pasting into a review, tutorial, or documentation to keep it presentable.
Security Audits
Beautify obfuscated scripts to inspect their behaviour before including them in your project.
Teaching & Learning
Show students the difference between minified and beautified code, and how formatting affects readability.
⚠️ Important Notes & Limitations
🔹 Safe by design: This beautifier only changes whitespace — it never renames variables, rewrites expressions, or reorders statements. Behaviour is preserved exactly.
🔹 ASI awareness: Newlines after return, throw, break, continue, and yield are preserved, so automatic semicolon insertion behaves exactly as before.
🔹 Not a full parser: This tool uses a token-based formatter rather than a full AST. It handles all common JavaScript correctly, but extremely exotic syntax may produce imperfect formatting. Always review the output.
🔹 Test after beautifying: Even though whitespace-only changes are safe in principle, always run your tests after applying formatted code to production.
❓ Frequently Asked Questions
A JS beautifier adds line breaks, indentation, and spacing to JavaScript code. It takes minified or badly formatted input and outputs code that follows consistent styling rules. Crucially, it does not change what the code does — only how it looks.
Absolutely 100% safe. This tool processes everything in your browser using vanilla JavaScript. No code is ever sent to any server, stored, or shared with third parties.
Whitespace-only changes are safe in JavaScript in almost all cases, provided the beautifier respects automatic semicolon insertion (ASI). This tool does — it never removes a newline after return, throw, break, continue, or yield. That said, always test after formatting just to be certain.
A minifier removes all unnecessary whitespace to shrink file size for production. A beautifier does the opposite — it adds whitespace to make code readable again. Use minification before deployment, and beautification for debugging, learning, or code review.
Yes! Once the page loads, the tool works entirely offline. You can bookmark it or save the page (HTML) for offline use.
Completely free, forever. No sign-up, no registration, no hidden fees, no usage limits. This tool is proudly offered by GenieDevs as a free resource for the developer community.
👨💻 About the Author — GenieDevs
📦 Get the Standalone Version
✨ JS Beautifier – Standalone Edition
Get the complete, self-contained HTML version of this tool. Perfect for offline use, intranet deployments, or embedding in your own projects. No dependencies, no external calls — just one HTML file that works anywhere.
🎯 Final Takeaway
The JS Beautifier is your go-to tool for making any JavaScript readable again. Whether you're debugging a minified production bundle, studying a library, or cleaning up legacy code, this tool restores clean structure without changing behaviour.
✨ Try it now — paste your JavaScript, click Beautify, and watch it transform. With its 100% browser‑based architecture, your code stays private.
🚀 Share this tool with your fellow developers. Explore our growing collection of free utilities at GenieDevs.