JavaScript Minifier
Minify and compress JavaScript code
Input JavaScript
Removes comments and debugger statements, keeps console logs.
Your code is never uploaded or stored.
Errors & warnings
JavaScript minification tips
- Test your minified JavaScript before deploying it.
- Keep original source files for debugging.
- Use name mangling with care when your code relies on function or class names.
- Combine minification with gzip or Brotli compression.
- Use build tools to automate minification in production.
Minified JavaScript
Compression results
- Original size
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- Minified size
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- Bytes saved
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- Compression
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- Lines
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Before & after
Before
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After
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About JavaScript Minifier Tool
Our free online JavaScript minifier compresses your JS code by removing whitespace, comments, and unnecessary characters to produce the smallest possible output. It fully supports modern ES6+ syntax, including arrow functions, template literals, classes, destructuring, and more.
Choose from three minification levels to match your needs. The Safe preset keeps all comments and variable names intact. The Recommended preset strips comments and debugger statements while preserving console logs. The Aggressive preset enables full name mangling, dead code elimination, and console log removal for maximum file size reduction.
Your JavaScript code is never uploaded to any server. The tool provides detailed compression statistics showing original size, minified size, bytes saved, compression percentage, and line count reduction. Simply paste your code, choose a preset, and get optimized JavaScript instantly.
Key Features
- Full ES6+ syntax support: arrow functions, classes, template literals and destructuring
- Three minification presets: Safe, Recommended, and Aggressive compression levels
- Dead code elimination to remove unreachable code paths
- Optional console.log and debugger statement removal
- Variable name mangling (shortening) in Aggressive mode for maximum compression
- Real-time auto-minification with debounced processing as you type
- Detailed compression statistics: original size, minified size, bytes saved, ratio, and line count
- Built-in syntax validation with bracket and parenthesis matching
- JavaScript file upload (.js) support for processing existing scripts
- One-click copy to clipboard and download as .js file
How to Use the JavaScript Minifier
- Select a minification level: Choose Safe for basic compression, Recommended for balanced optimization, or Aggressive for maximum file size reduction with name mangling.
- Input your JavaScript: Paste your JS code into the text area, upload a .js file, or click Load Sample to try a demonstration.
- Wait for processing: The tool automatically minifies your code after a short delay, showing a processing indicator during compilation.
- Review compression results: Check the statistics panel to see how much file size was reduced, including original and minified sizes, bytes saved, and line count.
- Copy or download: Click Copy to copy the minified JavaScript to your clipboard, or use Download to save it as a .js file.
Use Cases
- Production deployment: Minify JavaScript before deploying to reduce file sizes and improve page load speed.
- Performance optimization: Compress scripts to improve Core Web Vitals, Time to Interactive, and First Contentful Paint metrics.
- Bandwidth reduction: Smaller JS files reduce hosting costs and data transfer, especially for high-traffic websites.
- Mobile optimization: Compressed JavaScript loads faster on mobile networks, improving the experience for mobile users.
- Quick one-off minification: Minify individual scripts when you need a quick optimization outside of your build pipeline.
- Code review and analysis: Use the compression statistics to assess how much optimization potential your codebase has.
- Learning and experimentation: Understand how minification works by comparing before-and-after output across different preset levels.
Frequently Asked Questions
What is the difference between Safe, Recommended, and Aggressive modes?
Safe mode performs basic compression while keeping all comments, console logs, and variable names. Recommended removes comments and debugger statements. Aggressive enables name mangling, console removal, dead code elimination, and multi-pass optimization for the smallest output.
Will name mangling break my code?
Name mangling renames local variables to shorter names, which is safe for most code. However, it can cause issues if your code relies on function or variable names at runtime (e.g., through eval or reflection). Always test thoroughly after using Aggressive mode.
Does this support TypeScript or JSX?
This tool processes standard JavaScript (ES6+). TypeScript and JSX need to be compiled to plain JavaScript first before minification. Use your TypeScript compiler or Babel to transpile, then paste the output here.
Tips & Best Practices
- Always keep source files: Store your original, unminified JavaScript in version control and only minify for production builds.
- Generate source maps: Use source maps in your build pipeline to debug minified code in browser developer tools.
- Test after minification: Always run your test suite against minified code, especially when using Aggressive mode with name mangling.
- Combine with server compression: Pair JavaScript minification with gzip or Brotli compression on your web server for the best file size reduction.
- Start with Recommended: The Recommended preset offers the best balance of safety and compression for most projects.
- Remove console logs in production: Use Aggressive mode to automatically strip console.log statements that should not appear in production code.