JavaScript Minifier - Compress JS Online
Paste your JavaScript, click Minify, and get a compressed version with comments and whitespace stripped. Safe minification — no variable mangling.
What Is a JavaScript Minifier?
A JavaScript minifier compresses JS code by removing unnecessary characters like comments, extra whitespace, and line breaks. This tool performs safe minification — it strips comments and whitespace but does not rename variables or apply advanced transformations, ensuring your code stays readable and debuggable. Everything runs in your browser with no server uploads.
How to Use the JS Minifier
- Paste JavaScript — Enter or paste your JS code in the left input panel
- Click Minify JS — The compressed result appears in the right panel
- Check Size Stats — See original size, minified size, and percentage saved
- Copy Result — Click Copy Result to copy the minified JavaScript
Why Use This JS Minifier?
- Safe Compression — Removes comments and whitespace without mangling variable names
- Faster Loading — Smaller JS files improve page load speed and performance scores
- Comment Removal — Strips both // single-line and /* multi-line */ comments
- Size Comparison — See original vs minified byte counts and exact savings percentage
- Debuggable Output — Since variables aren't renamed, the output is still readable
- Privacy First — Your code never leaves your browser. Zero server processing
FreeToolbox vs Other JS Minifiers
| Feature | FreeToolbox | UglifyJS | javascript-minifier.com |
|---|---|---|---|
| Browser-based | Yes | Node.js | Server-side |
| No install needed | Yes | npm install | Yes |
| Variable mangling | No (safe) | Yes | Yes |
| Comment removal | Yes | Yes | Yes |
| Size comparison | Yes | CLI output | Yes |
| No ads | Yes | N/A | No |
| Dark theme | Yes | N/A | No |
FAQ
Does this tool rename my variables?
No. This tool only removes comments, whitespace, and line breaks. Variable names, function names, and all identifiers remain unchanged. This is intentional for safety — advanced mangling can break code that relies on variable names.
How much space does JS minification save?
With comment and whitespace removal only, typical savings range from 20-50% depending on how many comments and how much formatting the original code has.
Will minification break my code?
The safe minification approach (no variable renaming) is extremely unlikely to break anything. It only removes characters that JavaScript engines ignore — comments and whitespace.
Can I minify TypeScript with this tool?
This tool is designed for standard JavaScript. TypeScript should be compiled to JS first (using tsc), then minified. Type annotations would not be handled correctly.
Is my code sent to a server?
No. All minification happens locally in your browser using JavaScript. Your source code is never uploaded or transmitted anywhere.