JavaScript Minifier is a 100% free, browser-based utility that enables you to minify or beautify javascript with terser. Unlike traditional cloud converters, all processing executes locally on your device with zero server uploads, delivering immediate results and ironclad data privacy.
About the JavaScript Minifier
The JavaScript Minifier uses Terser, the same minifier used by webpack, Vite and Rollup, to shrink your scripts. It removes whitespace and comments, shortens local variable names (mangling) and applies safe compression such as removing dead code and folding constants.
Paste minified code and switch to Beautify mode to make it readable again. If your code has a syntax error, the tool shows the error message with its line and column so you can fix it quickly.
How to use the JavaScript Minifier
- Paste your JavaScript into the input box.
- Choose Minify (with mangle/compress options) or Beautify.
- Review the size savings or any syntax error, then copy or download the output.
Features
- Terser minification (ES2020+)
- Mangle & compress options
- Beautify minified code
- Syntax errors with line numbers
Why Choose In-Browser JavaScript Minifier vs Cloud Converters?
| Feature | Toolora (In-Browser) | Traditional Cloud Tools |
|---|---|---|
| Data Privacy | 100% Private (Files stay on device) | Uploaded to remote servers |
| File Size Limits | Unlimited (Limited only by your RAM) | Restricted (e.g. 10MB–50MB caps) |
| Processing Speed | Instant (Zero upload/download delay) | Slow upload & queue waiting |
| Ads & Popups | Clean, distraction-free | Heavy banner & interstitial ads |
Frequently asked questions
What does "mangle" do?
Mangling renames local variables and function parameters to short names like a, b and c. Global names and object properties are left alone so your code keeps working.
Does it support modern JavaScript?
Yes. Terser understands modern syntax including arrow functions, classes, async/await, optional chaining and ES modules.
Can I recover the original code from minified JavaScript?
Beautifying restores readable formatting, but original variable names and comments removed during minification cannot be recovered without a source map.