CSS/JS Minifier & Beautifier

Beautification is the reverse: it takes compact or minified code and reformats it with consistent indentation, newlines between declarations, and proper spacing. You need it when debugging third-party minified libraries (copy the minified code, beautify, then read it), when working with generated or concatenated CSS/JS that has no formatting, when reviewing legacy code that was never properly formatted, or when a code review requires readable diffs. It does not add comments or restore original variable names — only formatting is reconstructed.

This tool's minifier is conservative — it removes only whitespace and comments, which are never semantically meaningful. String literals (single-quoted, double-quoted, and template literals in JS), regular expressions, CSS selector and property values are all preserved exactly. One common pitfall: if your JavaScript depends on automatic semicolon insertion (ASI) and the code is structured ambiguously, minification that puts multiple statements on one line could theoretically cause issues. The safest approach is to always use semicolons explicitly and test minified output in your target browsers.

For production projects with a development workflow: use a build tool (Webpack, Vite, Rollup, esbuild, or Parcel) that integrates minification into your build pipeline. These tools offer more advanced optimizations: tree-shaking, module bundling, code splitting, source maps, and post-processing. This online tool is best for: one-off minification of legacy files without a build system, quickly checking minified size before committing to a build pipeline change, reading someone else's minified code by beautifying it, or small projects where setting up a build system would be overkill.

Upload .css or .js files up to 5MB per file. The tool auto-detects the mode based on the file extension. For text input (paste mode), there is no size limit but very large files may take a moment to process. Output can be downloaded as a .css or .js file. SCSS, TypeScript, and other preprocessed formats must be compiled to plain CSS or JavaScript first before minification.

Minification reduces file size by removing redundant characters. Gzip compression (applied by web servers for transfer) then compresses the minified file further. The key insight: minified code compresses better than original code because it has less character variety. The combination of minification + Gzip typically achieves 60-85% total reduction. Serving a 100KB CSS file: original + Gzip ≈ 25KB, minified + Gzip ≈ 15KB. The minification saves 10KB after Gzip. Without Gzip configured on your server, minification saves more in absolute terms but the relative gain is smaller.

No. All minification and beautification happens in your browser using JavaScript. Your CSS and JavaScript code, which may contain proprietary logic, API endpoints, or sensitive configuration, never leaves your device.

Not directly — the tool processes CSS and JavaScript separately because they have different syntax rules. If you have HTML files with embedded <style> and <script> blocks, you would need to extract each section, minify them separately, then reinsert. For full HTML+CSS+JS minification in one pass, use an HTML minifier that handles embedded code blocks, or use a build tool that processes all asset types together.