JavaScript Compressor with Source Map
Minify JavaScript and generate a Source Map v3 file online for free — no build tools needed. Our javascript compressor with source map produces the .min.js for production and the .map file for debugging, both downloadable as a ZIP. Runs entirely in your browser, so your code never leaves your device. No signup required.
JavaScript Input
Any JavaScript — ES5, ES6+, modules, scripts
Minified JS Output
Read-only — copy or download the minified output
About source maps
Source maps let browser DevTools map minified code back to the original source for debugging. Deploy the .min.js to production and keep the .map file on your server — the //# sourceMappingURL comment in the minified file tells DevTools where to find it.
Why Use Our JavaScript Compressor with Source Map?
Instant JS Minification with Source Map
Our javascript compressor with source map minifies your code and generates a valid Source Map v3 file instantly in the browser — no server round-trips, no build tools required. Get both the .min.js and .map files within seconds, ready for production deployment.
Secure JavaScript Compressor Online
Your JavaScript code never leaves your device. Our javascript compressor with source map online runs entirely client-side — no code is ever uploaded to any server. Safely minify proprietary business logic, API integrations, or sensitive application code without any privacy risk.
Source Map v3 Generation
Our javascript compressor generates a fully valid Source Map v3 JSON file with Base64 VLQ-encoded mappings, sourcesContent embedding, and correct sourceMappingURL comment. Browser DevTools can use the map to show original source during debugging — even in production.
100% Free Forever
Use our javascript compressor with source map completely free with no hidden costs, no signup, no ads, and no usage limits. Minify and generate source maps online as many times as you need — for personal projects, professional work, or enterprise use. Free forever.
Common Use Cases for JavaScript Compressor with Source Map
Production Deployment Optimization
Minify JavaScript files before deploying to production to reduce page load time and bandwidth costs. Our javascript compressor with source map generates the .min.js for serving and the .map file for debugging — the standard production workflow.
Debuggable Production Code
Deploy minified JavaScript while keeping the ability to debug in browser DevTools. Upload the .map file to your server alongside the .min.js — Chrome, Firefox, and Safari DevTools will automatically map minified code back to the original source.
CDN & Static Asset Delivery
Compress JavaScript files before uploading to CDN or cloud storage to reduce transfer costs and improve cache efficiency. Our javascript compressor online produces CDN-ready .min.js files with embedded sourceMappingURL for optional debugging.
npm Package Preparation
Minify JavaScript library files before publishing to npm. Our javascript compressor with source map generates the minified distribution file and source map that npm package consumers expect in the dist/ folder.
Quick Script Minification
Minify individual JavaScript files without setting up a full build pipeline. Our javascript compressor online is ideal for one-off minification tasks — bookmarklets, userscripts, inline scripts, and small utility files.
E-commerce & CMS Integration
Minify custom JavaScript for Shopify themes, WordPress plugins, or CMS integrations before deployment. Our javascript compressor with source map reduces script size without breaking functionality, with source maps for post-deployment debugging.
Understanding JavaScript Minification with Source Maps
What is a JavaScript Compressor with Source Map?
A JavaScript compressor with source map is a tool that minifies JavaScript code to reduce file size and simultaneously generates a Source Map v3 file that maps positions in the minified output back to the original source. This enables browser DevTools to show the original, readable code during debugging — even when serving minified JavaScript in production. Our free javascript compressor with source map online implements a tokenizer-based minifier and a Base64 VLQ source map encoder, running entirely in your browser with no server upload required.
How Our JavaScript Compressor with Source Map Works
- Paste or Upload Your JavaScript:Enter your JavaScript in the input panel or click "Upload .js" to load a file. Set the filename — it's used in the source map's
sourcesfield and the output filenames. - Configure and Minify:Choose your minification options (remove comments, collapse whitespace, remove console.log, remove debugger). Click "Minify + Generate Source Map" — all processing happens locally in your browser with complete privacy.
- Download Both Files:Download the .min.js and .map files individually, or click "Download Both (.zip)" to get them together. Deploy the .min.js to your server and place the .map file at the same path — the
//# sourceMappingURLcomment in the minified file tells DevTools where to find it.
What Gets Minified
- Comments Removed: Single-line (
//) and multi-line (/* ... */) comments are stripped from the output, reducing file size without affecting functionality. - Whitespace Collapsed: Unnecessary spaces, tabs, and newlines between tokens are removed. Spaces required between keywords and identifiers are preserved to maintain valid JavaScript syntax.
- Strings Preserved: String literals, template literals, and regular expressions are preserved verbatim — the minifier never modifies string content, preventing accidental breakage.
- Source Map Generated: A Source Map v3 JSON file with Base64 VLQ-encoded mappings, embedded
sourcesContent, and correctsourceMappingURLcomment is generated alongside the minified output.
How to Use the Source Map in Production
Deploy script.min.js to your web server or CDN. Place script.min.js.map at the same URL path (e.g., /js/script.min.js.map). The //# sourceMappingURL=script.min.js.mapcomment at the end of the minified file tells browser DevTools where to fetch the map. In Chrome DevTools, open the Sources panel — you'll see the original source file listed under the domain. For security, you can restrict access to the .map file using server rules so only developers can access it.
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Frequently Asked Questions About JavaScript Compressor with Source Map
A JavaScript compressor with source map is a tool that minifies JavaScript to reduce file size and generates a Source Map v3 file that maps positions in the minified output back to the original source. This lets browser DevTools show the original code during debugging. Our free javascript compressor with source map online runs entirely in your browser — no server upload required.
Our javascript compressor with source map uses a tokenizer-based approach that preserves all string literals, template literals, and regular expressions verbatim. Comments and whitespace are removed, and spaces between keywords are preserved. For complex code with eval(), with statements, or dynamic property access, test the minified output before deploying to production.
Absolutely. Our javascript compressor with source map processes everything locally in your browser using pure JavaScript. Your code is never uploaded to any server, never stored remotely, and never leaves your device. All minification and source map generation happens entirely on your machine.
Yes — 100% free, forever. No signup, no account, no premium tier, no usage limits, and no ads. Minify JavaScript and generate source maps online as many times as you need for any purpose.
A Source Map v3 is a JSON file that maps positions in minified code back to the original source using Base64 VLQ-encoded position data. When you open DevTools in Chrome, Firefox, or Safari, the browser fetches the .map file referenced by the //# sourceMappingURL comment and uses it to display the original source in the Sources panel — making debugging minified production code possible.
Place the .map file at the same URL path as the .min.js file. For example, if your minified script is at /js/script.min.js, put the map at /js/script.min.js.map. The //# sourceMappingURL=script.min.js.map comment at the end of the minified file tells DevTools where to fetch the map. You can restrict access to .map files using server rules so only developers can access them.
Our javascript compressor with source map offers: Remove comments (single-line and multi-line), Collapse whitespace (removes unnecessary spaces and newlines), Remove console.log() calls (useful for production builds), and Remove debugger statements. String literals and template literals are always preserved verbatim.
Terser and UglifyJS are full AST-based minifiers that can rename variables, inline constants, and perform dead code elimination — achieving 30–50% better compression than whitespace-only minification. Our javascript compressor with source map uses a tokenizer-based approach that is faster and simpler but achieves less compression. For production builds, consider using Terser in your build pipeline; use our tool for quick one-off minification tasks.
Our javascript compressor with source map works on JavaScript only — it does not understand TypeScript type annotations. To minify TypeScript, first compile it to JavaScript using the TypeScript compiler (tsc), then minify the compiled .js output with our tool. The generated source map will reference the compiled JS, not the original TypeScript.