What the JavaScript Minifier does
This is a live, two-pane minifier. Your original JavaScript sits on the left and the minified version appears on the right the moment you type, with no button to press. Each pane shows its own size, and a summary line reads out your original size, the minified size and how much smaller the result is, so you can see the saving as you work. Under the hood it removes block comments, collapses extra spaces and tabs, trims each line, and drops blank lines. It keeps your line breaks instead of crushing everything onto one line, which means automatic semicolon insertion stays safe and your script keeps working.
It is handy for front-end developers shipping a quick script, anyone tuning page speed, or students who just want a smaller file to paste into a project. Think of it as a fast cleanup pass rather than a full compiler. It is conservative and ASI-safe, so it will not rename variables or rewrite logic the way Terser or UglifyJS do, which keeps it predictable and easy to eyeball. When you are done, one click copies the output or downloads it as a .min.js file.
How to use it
- Paste or type your JavaScript into the input pane on the left, or hit Load example to drop in a sample script.
- The minified version appears in the right pane right away as you type, with each pane’s size and the percent saved shown above.
- Check the result, then click Copy to grab the cleaned code, or Download to save it as a
.min.jsfile. - Use Clear to empty both panes. Everything runs in your browser, nothing is uploaded.
Why minify here
Everything happens inside your browser. Your code is never uploaded, so private or unreleased scripts stay on your machine. It is free, needs no account, and runs instantly with no waiting on a server.
Because the output preserves line structure, it is also readable enough to scan if you want to confirm nothing broke. Smaller files mean fewer bytes over the wire and a quicker first paint for visitors on slow connections.
A quick tip
For production builds where you want variable renaming and aggressive size cuts, pair this with a full bundler like esbuild or Terser. This minifier is perfect for one-off snippets, inline scripts, and fast manual shrinking. If you regularly process whole folders of files, the BulkPro desktop app from the same team handles batch jobs.
Frequently asked questions
- Does this JavaScript minifier rename variables like Terser or UglifyJS?
- No. It removes block comments, extra spaces, tabs, and blank lines, but it does not rename variables or rewrite your code. That keeps the output predictable and easy to read. For variable mangling and maximum compression, use a full bundler like esbuild or Terser alongside it.
- Will minifying break my code with missing semicolons?
- No. The tool keeps line breaks instead of joining everything into one line, so JavaScript's automatic semicolon insertion still works correctly. Your script should run exactly as before, just with less whitespace and no comments.
- Is my JavaScript uploaded anywhere?
- No. All minifying runs locally in your browser. Your code never leaves your device, which makes it safe for private or unreleased scripts. There is no server round trip and no account needed.
- How much smaller will my file get?
- It depends on how many comments and how much indentation your code has. Heavily commented or deeply indented files shrink the most, while already-compact code sees a smaller drop. Each pane shows its size and the summary line reads out the original size, minified size and percent saved, all updating live so you see the difference instantly.
- Can I download the minified file?
- Yes. Next to Copy there is a Download button that saves the output as a .min.js file, ready to drop into your project or `<script>` tag.
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Last updated: June 15, 2026