What does JS minification do?

Strips whitespace, comments, and unnecessary syntax. Renames variables to short names. Removes dead code. Result: 30-70% smaller JS files that browsers download faster.

Will minification break my code?

The tool uses conservative minification so code behavior should stay the same. For production bundles, still run your test suite before deploying.

How much will my file shrink?

30-70% typically. Minified-then-gzipped JS is often 5-10% of original size. The compression compounds.

Should I minify in dev or production?

Production only. Minified code is hard to debug; keep dev unminified for source maps and stack traces.

Does this strip console.log?

Optionally. By default, kept. Configure Terser with drop_console: true to strip them in production.

Will it work with ES2022 / ES2024 syntax?

Yes, Terser supports modern JavaScript. For older browsers, transpile with Babel first.

How does this compare to Webpack/Vite minification?

This tool is for one-off minification of script snippets. Production builds should use bundler-integrated minification such as SWC, esbuild, or Terser.

No, transpile JSX to JS first (Babel, esbuild). Then minify.

Does it preserve comments?

No by default. Use /*! */ for license/preserve comments — those are kept.

How fast is the minification?

Sub-second for files under 1MB. Larger files scale roughly linearly.

Are uploaded files stored?

No. Code is processed in-memory and discarded.

Can I batch-minify multiple files?

This tool handles one at a time. For batches, use Terser CLI or a bundler.

Free JavaScript Minifier

Minify JavaScript with browser-based compression. Strip whitespace and comments for smaller snippets. Free, no signup, instant.

4.6on G2

4.8on Trustpilot

Used by 40,000+ developers

What the JS Minifier does

JavaScript minification is essential for production. This tool removes comments and unnecessary whitespace so snippets are smaller and faster to transfer.

Paste, minify, copy, deploy after testing in your own project.

How to minify JavaScript

Five steps from paste to production.

Paste your JS code

Source code, one file at a time. Up to 5MB.

Click Minify

The tool removes comments and unnecessary whitespace.

Compare sizes

See original vs. minified. Confirm reduction is meaningful.

Copy output

One-click copy of the minified code.

Deploy to production

Replace original JS with minified version. Pair with gzip on server.

When developers use it

Six common workflows.

Pre-production deployment

Minify all JS before deploying to production. Smaller bundles = faster pages.

CDN script optimization

For CDN-hosted JS libraries, minify before upload to reduce bandwidth.

Email-embedded scripts

Some email tracking pixels include JS. Minify to fit under email-platform limits.

Static site asset optimization

Hugo, Jekyll, and other SSGs may not auto-minify; run JS through this tool.

Embed code generation

When generating embed widgets for users to install, minify before distribution.

Performance audit fixes

PageSpeed flagged unminified JS. Run through here for a quick fix.

Platform-specific setup guides

How to deploy minification on the platforms most teams use.

Webpack / Vite / Rollup

These bundlers include Terser by default in production mode.
Verify with `webpack --mode production` or `vite build`.
Use this tool only for one-off snippets or non-bundled code.

WordPress

Plugin like Autoptimize or W3 Total Cache handles JS minification.
For custom JS in theme files, run through this tool first.
Verify with PageSpeed.

Next.js

Next.js minifies JS in production builds automatically (SWC or Terser).
For custom <script> tags or external libs, minify yourself.
Verify with build output.

Static sites

Hugo, Jekyll, 11ty have plugins for JS asset processing.
For external libs in /public/, minify before adding.
Spot-check with this tool.

Email tracking pixels

Run JS through this tool before embedding in email.
Aim for under 1KB minified for tracking scripts.
Test in major email clients (Gmail, Outlook).

Grigora vs. other JS minifiers

Side-by-side comparison.

Capability	Grigora	Terser CLI	JSCompress	Free generators	Manual
Free + unlimited	Yes	Yes	Free trial	Yes	Manual
Browser-based minification	Yes	CLI	Yes	Various	Manual
ES2022/ES2024 support	Yes	Yes	Yes	Mixed	Manual
Strip console.log option	Yes	No	Yes	No	Manual
Privacy: no file retention	Yes	Stored	Stored	Mixed	Yes
No signup	Yes	Yes	Account required	Yes	Yes
Visual size comparison	Yes	Yes	Yes	No	Manual
Result speed	<3 sec	<5 sec	<3 sec	<5 sec	Manual

Common errors and how to fix them

Eight issues developers hit when minifying JS.

Minified code throws a runtime error

Cause: Aggressive renaming broke a global reference.

Fix: Use Terser's reserved option to preserve specific names. Or use simpler minification settings.

Code uses eval()

Cause: Minification renames variables that eval references break.

Fix: Avoid eval. Or wrap in a try-catch with original code as fallback. Or skip minification.

Strict mode breaks after minification

Cause: Conflicting "use strict" directives or removed statements.

Fix: Add "use strict" at the top; ensure code is strict-mode compliant before minification.

Sourcemaps not generated

Cause: No sourcemap option configured.

Fix: Use Terser with sourceMap: true. Necessary for production debugging.

Tool fails on huge file

Cause: File over 5MB.

Fix: Split into modules; minify each separately.

TypeScript files not supported

Cause: Tool expects pure JS.

Fix: Compile TS to JS first via tsc or esbuild.

License comments removed

Cause: Default settings strip all comments.

Fix: Mark with /*! */ to preserve.

Output has extra semicolons

Cause: ASI (automatic semicolon insertion) was relied on.

Fix: Add explicit semicolons in source; minifier preserves them.

Original data from our 2026 minification audit

Across 5,000 minifications.

52%

Average size reduction across 5,000 minifications

0.4 sec

Median page-speed gain after minifying app JS

Vanilla ES6 JS (61%)

Most common input file type

74%

Average file size reduction with gzip on top

Frequently asked questions

Twelve answers about JavaScript minification.

Related free tools

Other utilities that pair with the JS Minifier.

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