Z

JavaScript Minifier

Minify JavaScript with terser. Mangle, compress, comment policies — and a before / after size comparison.

Free No signup Client-side Privacy friendly

Size:

Size: · saved %

Working…

How to use

  1. 1 Paste your JavaScript on the left.
  2. 2 Toggle Mangle / Compress and pick a comment policy.
  3. 3 Click Minify — see before / after size at a glance.

Why use this tool

  • Real terser engine — same minifier used by webpack, Rollup, and Vite.
  • Lazy-loaded — terser is fetched only when you click Minify, keeping the page light.
  • Side-by-side size comparison so you can see exactly what you saved.
  • Pure client-side — your source never leaves the browser.

Frequently asked questions

What is the difference vs obfuscation?

Minifying shortens names and compresses syntax for performance. Obfuscation goes further — flattens control flow, encodes strings, injects dead code. See the <a class="underline" href="/js-obfuscator">JS Obfuscator</a>.

Will it run on modern JS?

Yes — terser supports ES2020+ syntax including optional chaining, BigInt, top-level await.

Need to pretty-print it back?

Use the <a class="underline" href="/javascript-formatter">JavaScript Formatter</a> to reverse the layout (not the mangling).

Summary

JavaScript Minifier is a free developer utility by Zerethon Tools. Minify JavaScript with terser. Mangle, compress, comment policies — and a before / after size comparison. Runs entirely in the browser — no signup, no upload.

Category
Developer
Pricing
Free
Privacy
Browser-based
Signup
Not required

Privacy

Your data never leaves your browser unless explicitly stated. JavaScript Minifier runs entirely client-side — no server upload, no logging, no tracking of your input.

Related tools

JSON Formatter

Format, validate, and minify JSON online. Free, no signup — your data never leaves your browser.

Open tool

SQL Formatter

Format SQL queries online — beautify MySQL, PostgreSQL, SQLite, SQL Server, Oracle, and BigQuery.

Open tool

UUID Generator

Generate UUIDs online — v1, v4, v7, and Nil. Bulk generation up to 10,000. Free, no signup.

Open tool

Password Generator

Generate strong, cryptographically random passwords. Configurable length and character sets — runs in your browser.

Open tool

Build, share, and grow on Zerethon Social

Free signup. Earn points, collect achievements, and connect with creators worldwide.

Sign up free