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Minify JavaScript code to reduce file size. Remove whitespace, comments, and shorten code.
JavaScript is typically the largest and most expensive resource on a web page. Unlike images which can be lazy-loaded, JavaScript must be downloaded, parsed, compiled, and executed before the page becomes interactive. Every kilobyte of unnecessary whitespace, comments, and formatting directly delays the Time to Interactive (TTI) metric. Minification is the simplest and most effective first step in JavaScript optimization.
The minification process starts by identifying and preserving string literals and regular expressions, since these may contain characters that look like comments or whitespace but are meaningful. With strings protected, the tool then removes all single-line comments (// ...) and multi-line comments (/* ... */). Consecutive whitespace characters are collapsed, and unnecessary spaces around operators, braces, and semicolons are stripped. The result is functionally identical code in a fraction of the original size.
Minification reduces individual file sizes. Bundling combines multiple files into fewer HTTP requests. Tree shaking eliminates unused code (dead code elimination). For the best production performance, use all three together. Modern build tools like webpack, Vite, Rollup, and esbuild handle all of these in a single build step. This online tool focuses on minification and is ideal for quick tasks, testing snippets, or projects without a build pipeline.
This tool shows the original and minified sizes in bytes and kilobytes, along with the percentage saved. Typical savings range from 20% for already-compact code to 60% or more for well-commented, nicely formatted source code. When combined with server-side gzip or Brotli compression, total transfer size reductions can exceed 85%.
Pro includes tree-shaking analysis, bundle size visualization, and dead code detection.
JavaScript minification removes comments (both single-line // and multi-line /* */), collapses whitespace, removes unnecessary semicolons, and strips formatting. This reduces file size by 20-60% depending on how the original code is written, resulting in faster downloads and page loads.
Basic minification (whitespace and comment removal) is safe and should not break your code. This tool performs conservative minification — it does not rename variables, rewrite expressions, or perform advanced transformations that could alter behavior. For production use with advanced optimizations, consider tools like Terser or esbuild.
Minification removes unnecessary characters without changing code logic. Uglification (or mangling) goes further by renaming variables to shorter names (e.g., 'userName' becomes 'a'). This tool focuses on safe minification. For full uglification, use build tools like Terser, UglifyJS, or esbuild.
Absolutely. Minified JavaScript is a standard web performance optimization. All major build tools and CDNs serve minified JS. Google Lighthouse flags unminified JavaScript as a performance issue. This tool is great for quick one-off minification or testing.
JavaScript Minifier is part of BriskTool's collection of free online tools. All processing runs entirely in your browser for maximum privacy and speed.