JavaScript Minifier
Shrink JS file size with Terser — industry-standard compression
Minified JavaScript will appear here
Paste JavaScript above and click Minify
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JavaScript Minifier – Minify JS Online with Terser
Free JavaScript Minifier powered by Terser. Minify JS online: remove comments, compress code and compare file size, all in your browser with no upload.
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What is JavaScript Minifier?
JavaScript Minifier compresses your code with Terser, the minifier Webpack uses by default. Paste plain JavaScript to remove comments, fold constants and eliminate dead code, then compare the original and minified size and download the result. Top-level names stay unmangled, and JSX must be transformed to plain JavaScript first. Everything runs in your browser, so your source code is never uploaded.
- javascript
- minifier
- terser
- compress
- optimize
- js
Features
What you get with JavaScript Minifier.
Powered by Terser
Uses the same minifier Webpack ships by default, for production-grade JavaScript compression.
Compression & Dead-Code Elimination
Simplifies expressions and strips unreachable code in two optimization passes.
Size Comparison
See original vs. minified byte count and percentage saved after each run.
How to use JavaScript Minifier
Follow these steps to get the best results.
Paste your JavaScript
Paste plain JavaScript (ES2022+ is fine; transform JSX to JS first).
Click Minify
Run Terser — comments are removed and code is compressed in two passes.
Compare and copy
Check the size reduction, then copy or download the minified script.
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Frequently asked questions
Common questions about JavaScript Minifier.
Yes — everything runs in your browser using Terser. Your code is never sent to any server.
No — top-level names are left as-is so the minified output stays easier to debug. This tool focuses on compression (removing comments, whitespace, and dead code) rather than name mangling.
Yes — Terser supports modern JavaScript including ES2022+ syntax. For JSX, transform to plain JS first (e.g., with Babel) before minifying.
Typical savings are 20–40% from comment and whitespace removal alone. Heavily commented, loosely formatted code sees the biggest reductions.
Terser is the open-source JavaScript parser, compressor and mangler that Webpack uses by default and that Vite supports as a minifier option. This JavaScript Minifier runs Terser in your browser, so you can minify a file without installing anything. To use it in a project instead, install it with npm and run: npx terser input.js --compress --mangle --output input.min.js
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