Code Minifier
Minify JavaScript, CSS and HTML instantly. Real-time size reduction stats. Free, private, no upload.
Input
Output
Minified output will appear here
About Code Minifier
Every unnecessary character in your JavaScript, CSS, and HTML adds bytes that users must download before your page renders. Whitespace, comments, long variable names, and unnecessary semicolons are all readable in source code but wasteful in production. Minification removes all of these without changing how the code executes, often reducing file sizes by 40–70%.
Our Code Minifier handles JavaScript (removing whitespace, comments, and shortening variable names where safe), CSS (eliminating whitespace and combining equivalent rules where possible), and HTML (removing unnecessary spaces, newlines, and redundant attributes). The minified output is production-ready — it behaves identically to the source code but in far fewer bytes.
When combined with server-side gzip or Brotli compression, minified assets achieve even smaller file sizes over the network. A CSS file minified from 50 KB to 30 KB might transfer as only 8 KB gzipped. These savings compound across pages and return visits, improving Time to First Byte, First Contentful Paint, and Core Web Vitals scores — particularly for users on slower mobile connections.
How to Use Code Minifier
- 1Paste your JavaScript, CSS, or HTML code into the input field.
- 2Select the language from the dropdown if it is not auto-detected correctly.
- 3Click "Minify" to produce the minimized output with whitespace and comments removed.
- 4Review the file size comparison showing original versus minified byte count.
- 5Click "Copy" to copy the minified code or "Download" to save it as a new file.
Use Cases
- →Minify a JavaScript bundle for production deployment to reduce initial load time
- →Compress a CSS stylesheet before publishing a static website
- →Reduce HTML file size for email templates or landing pages where every byte counts
- →Quickly minify a third-party snippet to include inline in a webpage or email
- →Prepare minified assets for CDN delivery where smaller files reduce bandwidth costs
- →Reduce the size of generated CSS from CSS-in-JS tools before adding to a critical path
Tips
- ✓Always keep your original unminified source files — minified code is effectively uneditable
- ✓Minification plus gzip compression achieves even smaller transfers — both layers work together
- ✓Use the Code Formatter tool to reverse-minify (beautify) received code for debugging
- ✓JavaScript minification can rename local variables to single letters — safe for production, unreadable in debugging
- ✓For build pipelines, use dedicated tools like Terser (JS), cssnano (CSS), or html-minifier in CI
- ✓The file size counter shows you the exact byte reduction so you can measure the impact
Frequently Asked Questions
Minification removes all unnecessary characters from source code — whitespace, comments, long variable names — without changing its behavior. The result is a smaller file that loads faster in browsers.
Typical results: JavaScript sees 60–80% reduction, CSS sees 30–60% reduction, HTML sees 10–30% reduction.
CSS and HTML minification is fully reversible — it only removes whitespace and comments. JavaScript minification with variable renaming is not easily reversible. Always keep your original source files.
JavaScript is minified using Terser, the industry-standard JS minifier used by Webpack, Vite, and most modern build tools.
Yes. Terser supports modern JavaScript including arrow functions, template literals, destructuring, async/await, optional chaining, and all ES2020+ features.
No. All minification runs entirely in your browser. Your code never leaves your device.