What is JavaScript minification?
JavaScript minification removes unnecessary characters from source code — whitespace, comments, and line breaks — without changing functionality. Advanced minification also shortens variable names and simplifies expressions. This tool processes your code entirely in the browser.
Why minify JavaScript
Minifying JavaScript removes whitespace, line breaks, and comments to shrink the file the browser must download and parse. Because scripts are often the largest and most expensive part of a page to load and execute, reducing their size directly improves load time and interactivity — a key factor in Core Web Vitals.
Minification preserves behaviour exactly: the program runs the same, it is simply delivered in fewer bytes.
Minification and your source
Write and maintain readable JavaScript, and minify as a build step before deploying. Keeping the formatted source as your working copy while serving the minified file to users gives you smaller downloads without sacrificing maintainability. For deep size reductions, production build tools also rename local variables, which this quick minifier leaves untouched.
Minifying, bundling, and compression
In a production pipeline, minification is one of several steps: a bundler combines modules, minification removes whitespace and comments, and the server compresses the result with gzip or Brotli. Each step reduces size differently, and together they make scripts load far faster than the original source.
How to minify JavaScript
- 1Paste your code. Paste the JavaScript you want to compress.
- 2Click Minify. Whitespace, line breaks, and comments are removed to shrink the file.
- 3Copy the result. Use the minified code in production; keep your formatted source for editing.
Examples
Compress a function
Input
function add(a, b) {
// sum
return a + b;
}Output
function add(a,b){return a+b}Bytes saved
Input
Formatted: 110 bytes
Output
Minified: 41 bytes (about 63% smaller)
What JS minification removes
Bytes stripped without changing behaviour.
| Removed | Kept |
|---|---|
| Comments | Statements and logic |
| Whitespace and newlines | Variable and function names |
| Indentation | String and value contents |
| Redundant spaces | Program behaviour |
Frequently asked questions
Does minifying change what my code does?+
No. Minification only removes whitespace and comments. The program behaves identically; it is just smaller.
Why minify JavaScript?+
Scripts are often the heaviest part of a page to download, parse, and run. A smaller file loads and becomes interactive faster, improving Core Web Vitals.
Does it rename my variables?+
This quick minifier removes whitespace and comments but keeps names readable. Full production bundlers also shorten local variable names for further savings.
Should I keep the original code?+
Yes. Maintain your formatted source and minify as a build step, so your code stays editable while users get the compressed file.
Is my code private?+
Yes. Minification runs in your browser; nothing is uploaded.
Is it free?+
Yes — free with no limits.
Is minified code the same as obfuscated code?+
No. Minification shrinks code while keeping it functional; obfuscation deliberately makes code hard to read. Minified code is simply compact, not hidden.