How can I minify JavaScript online for free?

Paste your JavaScript into the JavaScript Minifier and click minify. Powered by Terser, it mangles variable names, removes dead code, and strips comments — then reports exact byte savings. If your code has a syntax error, it shows you precisely where.

What does a JavaScript minifier do?

It parses your code and rewrites it smaller: removing whitespace and comments, shortening variable names, simplifying expressions, and dropping dead code. The behavior stays the same; the file just downloads and parses faster.

Is this a real minifier or just whitespace removal?

Real. It uses Terser, the industry-standard JS minifier, running in your browser. It parses the code into an AST, so it can safely compress and mangle in ways regex-based tools cannot.

What if my code has a syntax error?

You get a clear Terser error message pointing at the problem instead of silently broken output. Fix the syntax and minify again.

Should I turn mangling on or off?

On for production: mangled names shrink files significantly and are safe. Off when you need readable stack traces or when another tool consumes the output and depends on specific names.

Is my code uploaded anywhere?

No. Terser runs locally in your browser. Your source code never leaves your device.

DEVELOPER TOOLS · FREE ONLINE TOOL

JavaScript Minifier

Real Terser-powered JS minification: parse, compress, mangleReadable JavaScript is written for humans: descriptive names, comments, generous line breaks. Browsers need none of that. This minifier compresses your script into its smallest valid form, producing dense code that executes identically while weighing measurably less.

✓ Free to use✓ No sign-up✓ Ready in your browser

// JAVASCRIPT MINIFIER · GET STARTED

Use JavaScript Minifier

Real Terser-powered JS minification: parse, compress, mangle

JavaScript to minify

Options

Mangle variable names (smaller output; turn off if you need readable names)

// JAVASCRIPT MINIFIER · HOW IT WORKS

How to use the JavaScript Minifier

Paste JavaScript

Paste your JavaScript into the box.

Pick options

Choose whether to mangle variable names.

Minify and copy

Click "Minify JavaScript", then copy or download the result.

// JAVASCRIPT MINIFIER · ABOUT THIS TOOL

About the JavaScript Minifier

Simple whitespace strippers leave most of the savings on the table and can break code. This tool runs Terser, the same minifier behind most production build pipelines, directly in your browser. Because it truly parses your code, it compresses expressions, removes dead code and reports syntax errors clearly. Production-grade minification without installing anything.

Where it helps most

Outside the build pipeline.

CMS code boxes

A snippet destined for a CMS custom-code box, where no bundler ever runs.

Userscripts and bookmarklets

Userscripts and bookmarklets that ship as a single compressed file for easy install.

Embed codes

Third-party embed code you were told to paste as-is, slimmed down before it goes live.

Quick experiments

Experiments where configuring a bundler would take longer than the task itself takes.

Minifying safely

Two habits keep it trouble-free.

Keep the source

Always keep the readable source as the file you edit; debugging compressed code directly is miserable.

Test after replacing

Breakage after minifying almost always exposes a pre-existing syntax quirk, so test the page once.

Pipeline projects

Projects with a build pipeline already minify on every deploy; those tools should stay the source of truth.

JavaScript Minifier: private by design

Everything runs in your browser. Your code never leaves your device, no signup needed.

// JAVASCRIPT MINIFIER · COMMON QUESTIONS

JavaScript Minifier FAQs

How much smaller will my JavaScript get?

Hand-written scripts typically shrink by 30 to 50 percent, since comments, descriptive names, and formatting make up a large share of the source. Already-minified libraries will barely change, so there is no benefit in minifying those twice.

Can minifying break my code?

Should I use this instead of a build tool?

How do I debug minified JavaScript?

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