HTML/CSS/JS Minifier
Code Minifier & Beautifier
Minify code for production or beautify for readability. Select your code type below.
Why Minify Code?
Faster Load Times
Smaller files transfer faster over the network, improving page load performance and user experience.
Reduced Bandwidth
Minified code uses less bandwidth, lowering hosting costs and improving mobile user experience.
Typical Savings
- HTML: 10-30% reduction
- CSS: 20-40% reduction
- JavaScript: 30-60% reduction
Best Practices
- Keep source files unminified
- Minify during build process
- Use source maps for debugging
- Combine with gzip compression
How to Use This Tool
- Select Code Type: Choose the HTML, CSS, or JavaScript tab based on your code. Each language has specific minification rules and options tailored to its syntax.
- Paste Your Code: Enter your code in the input textarea, or click "Load Sample" to see the tool in action. The input preserves your original code for comparison.
- Configure Options: Enable or disable options like removing comments, collapsing whitespace, and shortening variable names. For production, enable all optimizations; for debugging, use beautify instead.
- Click Minify or Beautify: "Minify" compresses code for production deployment; "Beautify" formats code with proper indentation for readability. Copy the result using the Copy button.
Technical Details
Minification reduces code size by removing unnecessary characters without changing functionality. For HTML: whitespace between tags is collapsed, comments removed, and optional closing tags omitted. For CSS: whitespace, comments, and redundant semicolons are stripped; shorthand properties are used where possible. For JavaScript: whitespace and comments are removed; in advanced minifiers, variable names are shortened.
This tool performs safe minification—transformations that never change code behavior. Production minifiers like Terser (JS), cssnano (CSS), and html-minifier add aggressive optimizations: dead code elimination, property merging, and tree shaking. Minification typically reduces file sizes by 30-70%. Combined with gzip compression, total savings can exceed 90%. Always test minified code before deployment.
Common Mistakes to Avoid
- Minifying Already-Minified Code: Running minification twice rarely helps and can break some code. If your file ends in .min.js or .min.css, it's already minified. Check for version without .min for the source.
- Debugging Minified Code: Minified code is unreadable. Generate source maps during build to enable browser DevTools to show original line numbers. Never deploy without source maps for debugging capability.
- Breaking Semicolon-Insertion: JavaScript's automatic semicolon insertion (ASI) can cause bugs when minified if semicolons are omitted inconsistently. Always use explicit semicolons, or use a linter that enforces consistent style before minification.
Related Tools
Need to format SQL queries rather than web code? Use our SQL Formatter for database queries. For validating JSON data structures before embedding in JavaScript, try the JSON Validator.
Frequently Asked Questions
Does minification affect code functionality?
Safe minification (removing whitespace and comments) never changes functionality. Aggressive minification (variable renaming, dead code removal) is functionally equivalent but can cause issues if code relies on function.name or eval(). This tool uses safe minification only.
Should I minify code during development?
No—work with unminified code during development for readability and debugging. Minify only for production builds. Most build tools (Webpack, Vite, Rollup) handle this automatically based on build mode.
How much file size reduction should I expect?
Typically 30-50% for CSS and HTML, 40-70% for JavaScript. Results vary based on code style—heavily commented, verbose code shrinks more. Combined with gzip, total bandwidth savings can exceed 80-90%.