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Code Minifier

JavaScript Minifier Online — Free JS CSS HTML Minifier Tool

Use our JavaScript minifier online to instantly minify JS, CSS, and HTML code. This free JS minifier reduces file sizes and speeds up your website.

Code Minifier

Reduce file size instantly

Original Code
0 bytes
Minified Code

About Code Minifier

Code Minifier compresses CSS, JavaScript, and HTML to reduce file sizes and improve website performance. Frontend developers and DevOps teams use this tool to shrink code for production deployment, cutting bandwidth and improving page load times for users worldwide.

How to use this tool

  1. Enter or paste your code minifier input into the tool interface.
  2. Adjust any available options for the result format, output style, or calculation settings.
  3. Click the action button to minify code and wait for the updated output.
  4. Review the result, then copy or download the output for your next task.

Example

Input

function add(a, b) { return a + b; }

Output

function add(a,b){return a+b;}

Tool guide

Minification strategies beyond whitespace removal

JavaScript minification goes far beyond stripping comments and whitespace. Advanced minifiers rename local variables to single letters, eliminate dead code branches, inline constant expressions, and even rewrite if-else chains into ternary operators. Our tool applies these transformations safely, preserving semantics while reducing the AST footprint. For production builds, pair minification with tree-shaking so unused exports are removed before the minifier runs.

HTML minification is trickier because it must respect conditional comments, inline SVG, and script template literals. Our minifier handles these edge cases by parsing the DOM structure rather than using naive regex. CSS minification similarly merges identical selectors, removes unused @keyframes, and compresses color values to their shortest hex form (e.g., #ff8800 → #f80).

When NOT to minify

Avoid minifying code that will be consumed by other tools or libraries — for instance, Web Workers, service workers, or dynamic import() paths often depend on readable function names. Similarly, polyfill bundles that need to remain self-documented should stay unminified during development. Our tool lets you toggle specific transformations so you can keep names readable while still removing whitespace.

Server-side rendering (SSR) frameworks like Next.js and Nuxt handle minification at build time. Minifying their output again can double-process templates and cause hydration mismatches. Let the framework handle it and use this tool for standalone scripts, bookmarklets, or inline <script> blocks.

Frequently asked questions

Does minification always break stack traces?

Yes, if you do not publish source maps. Without source maps, errors point to the minified file (e.g., main.js:1:2345). Generate a .map file and upload it to your error tracking service (Sentry, Datadog) to restore readable stack traces.

Can I minify and obfuscate at the same time?

Minification and obfuscation are separate goals. Minification reduces size; obfuscation intentionally makes code hard to reverse-engineer. Our tool focuses on safe size reduction. For obfuscation, use a dedicated tool that renames strings, inserts junk code, and applies control-flow flattening.

What is the difference between UglifyJS, Terser, and esbuild minification?

Terser (fork of UglifyJS) supports ES6+ syntax and is the standard for Webpack 5. esbuild minifies 10-100x faster but applies fewer optimizations. Our tool uses Terser-style transformations for maximum compression while being compatible with modern JavaScript.

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Related Reading

  • JavaScript Code Minification: A Practical Guide

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Expertise: Web development, SEO, and digital tools since 2020

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