JavaScript & CSS Minifier

What is a Code Minifier?

A code minifier is a tool that compresses JavaScript and CSS files by removing unnecessary characters like whitespace, comments, and line breaks without changing functionality. Minification significantly reduces file sizes (typically by 40-70%), which improves website load times, reduces bandwidth costs, and enhances overall performance. This tool uses a lightweight browser-compatible minification engine that works entirely in your browser for maximum privacy and security.

How to Use This Tool

1. Select either the JavaScript or CSS tab depending on the type of code you want to minify
2. Paste your code into the input area on the left, or click "Load Sample" to see an example
3. Configure minification options: for JavaScript, choose compression, mangling, and comment preservation; for CSS, select optimization level and comment handling
4. Click "Minify Code" to compress your code with the selected options
5. Review the minified output in the right panel and check the compression statistics showing file size savings
6. Use "Copy Output" to copy the minified code to your clipboard, or "Download" to save it as a file
7. If there are any syntax errors, they will be displayed with helpful error messages to help you fix the issue

Common Use Cases

• Production Deployment: Minify JavaScript and CSS files before deploying to reduce page load times and bandwidth usage
• Website Performance: Improve Core Web Vitals scores and SEO rankings by reducing file sizes
• Mobile Optimization: Decrease data transfer for mobile users with limited bandwidth
• Build Pipeline: Integrate minification into your build process for automated optimization
• CDN Preparation: Prepare optimized assets for content delivery networks
• Legacy Code: Minify older JavaScript and CSS files that lack modern build tools
• Quick Testing: Test how minification affects your code before adding it to your build process

JavaScript Minification

This tool uses a custom browser-compatible JavaScript minifier designed for simplicity, speed, and privacy. It provides:

• Universal JavaScript Support: Works with ES5, ES6+, and modern JavaScript features including arrow functions, async/await, classes, and template literals
• Compression: Removes whitespace, line breaks, and unnecessary characters to reduce file size
• Comment Removal: Strips single-line and multi-line comments while preserving license comments (starting with /*!)
• License Preservation: Option to keep important license comments for legal compliance
• Safe Processing: All operations maintain the exact behavior and functionality of your original code
• Client-Side Only: Runs entirely in your browser with no server uploads for maximum privacy

CSS Minification

CSS minification uses a custom browser-compatible optimizer with multiple optimization levels:

• Level 0 (None): Basic minification - removes whitespace and comments only
• Level 1 (Basic): Standard optimizations including hex color shortening (#aabbcc → #abc), decimal simplification (0.5 → .5), and zero-unit removal (0px → 0)
• Level 2 (Aggressive): Advanced optimizations like URL quote removal and margin/padding value simplification
• Modern CSS Support: Handles flexbox, grid, custom properties (CSS variables), and all CSS3+ features
• Important Comments: Option to preserve comments marked with /*! */ for attribution or licensing

Features

• Dual Language Support: Minify both JavaScript and CSS in a single tool with tabbed interface
• Lightweight & Fast: Browser-compatible minification engine with no external dependencies
• Detailed Statistics: View original size, minified size, bytes saved, percentage reduction, and compression ratio
• Customizable Options: Configure compression level and comment preservation settings
• Syntax Highlighting: Color-coded output for better code readability
• Error Detection: Clear error messages help identify and fix syntax problems
• One-Click Copy: Copy minified code to clipboard instantly
• File Download: Download minified code as .js or .css file
• Client-Side Processing: All minification happens in your browser - your code stays private and secure
• Sample Code: Load example code to test the tool and see typical compression results

Frequently Asked Questions

Is this minifier free to use?

Yes! This JavaScript and CSS minifier is completely free with no registration required, no file size limits, and no usage restrictions.

Is my code secure and private?

Absolutely. All minification happens entirely in your browser using JavaScript. Your code never leaves your computer and is never sent to any server, making it completely safe to use with proprietary code, client projects, or sensitive business logic.

How much can I reduce file sizes?

Typical results: JavaScript files reduce by 40-60% with compression enabled. CSS files typically reduce by 30-50% depending on the original formatting and optimization level. Heavily commented or formatted code can see even greater reductions.

What's the difference between compression and mangling?

Compression removes whitespace, comments, and line breaks without changing variable or function names. This provides most of the file size benefits while keeping the code somewhat readable. Mangling (in advanced minifiers) shortens variable and function names to single letters for maximum size reduction - this feature is not included in this lightweight browser-based tool to ensure code safety and reliability.

Does minification affect code functionality?

No. This minifier is designed to preserve the exact functionality of your code while reducing file size. All transformations are safe and only remove unnecessary whitespace and comments. However, always test minified code in your application to ensure it works as expected, especially if using advanced features or edge cases.

Should I minify code in development?

No. Keep your code unminified during development for easier debugging and readability. Only minify code for production deployment. Modern build tools (Webpack, Vite, Parcel) can automate minification as part of your build process.

What about source maps?

This web tool doesn't generate source maps, which are needed for debugging minified code in production. For projects requiring source maps, use build tools like Webpack or Vite that support source map generation alongside minification.

Can I minify TypeScript or SCSS?

This tool works with compiled JavaScript and CSS. If you have TypeScript or SCSS, first compile it to JavaScript/CSS using the appropriate compiler (tsc for TypeScript, sass for SCSS), then use this tool to minify the output.

Does this work offline?

Once the page is loaded, all minification functionality works offline. The minification engine is built into the page and doesn't require an internet connection to process code.

Are there keyboard shortcuts available?

Yes! Use Tab to navigate between buttons and text areas, Enter to activate focused buttons, and Escape while focused on text areas to quickly clear content.