Free Online JavaScript Minifier

JavaScript minification removes unnecessary characters from JS source code -including whitespace, line breaks, comments, and sometimes shortens variable names -without changing the code's functionality. The result is a smaller file that browsers execute identically but download and parse faster.

JavaScript minification typically reduces file size by 20–60%, depending on the original code style and comment density. Well-commented, nicely formatted code sees the largest reductions. Popular libraries like jQuery see about 50% reduction from minification alone, with further gains from gzip/Brotli compression.

Properly implemented minification does not break code. It only removes characters that the JavaScript engine ignores. However, issues can arise with code that relies on Function.prototype.toString() or eval with specific formatting. Always test your minified code before deploying to production.

Minification focuses on reducing file size while keeping code functional and somewhat readable. Obfuscation deliberately makes code difficult to understand by renaming variables to meaningless characters, adding dead code, and transforming logic. Obfuscation is for intellectual property protection, not performance.

Yes. Minifying JavaScript is a standard production optimization. All major build tools -Webpack (Terser), Vite (esbuild), Rollup, and Parcel -include JS minification by default. This online tool is useful for quick one-off minification, embedded scripts, and projects without a build pipeline.

This tool processes standard JavaScript. TypeScript must first be compiled to JavaScript using the TypeScript compiler (tsc) or a bundler like Vite or esbuild. Once compiled to JS, paste the output here for minification. Most build tools combine TypeScript compilation and minification in a single step.

Tree shaking removes entire unused exports and functions from your code bundle, while minification removes unnecessary characters from the remaining code. Tree shaking requires ES module (import/export) syntax and is performed by bundlers like Webpack and Rollup. Both techniques are complementary for optimal file size.

JavaScript is the most expensive resource type on the web because it must be downloaded, parsed, compiled, and executed. Smaller JS files reduce download time, decrease parse/compile time, and reduce main-thread blocking -directly improving Total Blocking Time (TBT), Time to Interactive (TTI), and Interaction to Next Paint (INP).

With a basic whitespace-and-comment minifier, yes -no variable names are changed, so dynamic references remain intact. If you use a more aggressive minifier that mangles variable names (like Terser with full optimization), eval() and bracket notation with string literals can break because the referenced names no longer match. This tool performs safe minification without name mangling.

Minified code is harder to read in browser DevTools, but modern browsers support source maps that map minified code back to the original. For production deployments, generate a source map alongside your minified file. If you only need to quickly minify a snippet without a source map, keep the original copy somewhere safe so you can make future edits to readable code.

Removing whitespace and comments typically reduces file size by 20–40% for well-commented, readable code. If you add gzip or Brotli on top, the total reduction from original to compressed-minified is often 70–85% compared to original uncompressed. The exact amount depends heavily on how much whitespace and documentation your code contains.