JavaScript Minifier Online

• Runs in your browser
• No upload
• No sign-up
• 100% Private
• Live size report
• Works on mobile

How to minify JavaScript online in 3 steps

1. 1

   Paste your JS

   Paste your raw, unminified JS code into the left text box. The tool works entirely in your browser.

2. 2

   Choose options

   Toggle options like removing comments or collapsing whitespace to get the exact output you need.

3. 3

   Copy or Download

   Click Copy to grab the minified JS, or download it directly as a .js file for production.

JavaScript minification example: before and after

The minifier removes comments, indentation and line breaks. The code behaves exactly the same, but the file is smaller.

// Add two numbers
function addNumbers(a, b) {
  /* return the sum */
  return a + b;
}

console.log(addNumbers(2, 3));

function addNumbers(a,b){return a+b}console.log(addNumbers(2,3));

JavaScript minification best practices

Follow these six habits to get faster pages without breaking your code.

1. 1

   Keep your original source

   Always store the unminified file in version control. Minified code is only meant for production.

2. 2

   Minify as the last step

   Minify after you have finished editing and bundling, so you do not have to edit unreadable code.

3. 3

   Serve with Gzip or Brotli

   Enable compression on your server or CDN. Minification and compression work together, and the Gzip estimate here shows the combined effect.

4. 4

   Test the minified file

   Load the minified file in a staging page and check the browser console for errors before you deploy.

5. 5

   Use a build tool for large apps

   For big projects, let Vite, Webpack or esbuild minify during the build. Use this tool for quick files, snippets and checks.

6. 6

   Cache with versioned file names

   Add a version or hash to the file name, for example app.min.js?v=2, so visitors get the new file after you update it.

JavaScript minifier FAQ: questions people ask

Quick answers about minifying JS, PageSpeed, Gzip, Terser, privacy and safety.

JavaScript minification glossary

Short definitions of the terms you will meet when optimizing JavaScript for speed.

Minification

Removing characters that are not needed to run the code, such as comments, spaces and line breaks, without changing what the code does.

Gzip

A compression format that web servers use to shrink files while they travel over the network. The browser unpacks the file on arrival.

Brotli

A newer compression format supported by modern browsers over HTTPS. It often produces smaller files than Gzip.

Obfuscation

Deliberately making code hard for humans to read, usually to discourage reverse engineering. It is different from minification.

Tree shaking

A build step that removes exported code your app never uses. It needs a bundler and is not done by whitespace minifiers.

Source map

A file that maps minified code back to your original source so browser dev tools can show readable code while debugging.

Bundling

Combining many JavaScript files into one or a few files so the browser makes fewer requests.

Everything you get for free

• One-click Minification

  Instantly remove all unnecessary whitespace, line breaks, and comments from your JS file with a single click.

• Live Size Report

  See exactly how many bytes you saved and what percentage of the original file size was reduced.

• Gzip Estimate

  Get an estimate of what your file size will be after Gzip compression, which is what most servers use.

• Remove Comments

  Strip out all // and /* ... */ comments. Perfect for production environments where code readability does not matter.

• Collapse Whitespace

  Remove every unnecessary space, tab, and newline character, reducing your JS to its absolute minimum size.

• Copy to Clipboard

  Instantly copy the minified JS to your clipboard for easy pasting into your code editor or build pipeline.

• Download as .js

  Download your minified code directly as a .js file, ready to upload to your web server.

• Privacy First

  All processing happens locally. Your proprietary code never leaves your computer, making it 100% safe.

What people use it for

• Web Developers

  Quickly minify JS before pushing to production. Reduce page weight and improve loading times for your users.

• WordPress Users

  Minify custom JS added to your theme or child theme to ensure your site loads as fast as possible.

• E-commerce Stores

  Every kilobyte counts for conversion rates. Minify your store JS to keep bounce rates low and sales high.

• PageSpeed Optimization

  Improve your Google Lighthouse scores by reducing the time it takes for the browser to download and parse JS.

• React & Vue Builds

  Before running a full Webpack or Vite build, quickly test how small your JS can get with basic minification.

• Learning & Teaching

  Show students the difference between readable, commented JS and the compressed code that actually ships to browsers.

ToolDeck vs build tools and other online JS minifiers

Many online minifiers upload your code to a server. This one runs locally in your browser. Build tools like Terser go further with variable renaming, but need installation and configuration.

Speed up the rest of your page

JavaScript is only one part of page weight. Minify your CSS and HTML and compress your images to get the full benefit.

• CSS Minifier

  Compress your stylesheets the same way, with a live size report and Gzip estimate.

• HTML Minifier

  Minify HTML, including inline CSS and JavaScript, to cut page weight.

• Image Compressor

  Images are often the heaviest part of a page. Shrink them in your browser too.

• JSON Formatter

  Format, validate or minify JSON used by your scripts and APIs.