JavaScript Minifier — Compress & Shrink JS With Terser

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 JavaScript Minifier?

A JavaScript Minifier is a tool that compresses JavaScript source code to reduce its file size for faster delivery. Built on terser, it offers control over name mangling, compression, and comment policies, and shows a before-and-after size comparison. Running entirely in the browser, it minifies code client-side so scripts are never uploaded to a server.

Features

Example

function add(a, b) {
  // sum two numbers
  return a + b;
}

function add(n,d){return n+d}

Common use cases

1. 1

   Shrink a script before shipping

   Cut bytes on a standalone JS file to speed up page load.

2. 2

   Quick one-off minify

   Minify a snippet without wiring up a build tool.

3. 3

   Compare compression settings

   Toggle mangle/compress and watch the size delta to tune output.

References

• Terser — JavaScript mangler and compressor — GitHub
• Minification — MDN Web Docs Glossary — MDN

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