JavaScript Minifier & Compressor

Reduce JavaScript file size instantly by stripping comments and whitespace. Dependency-free, privacy-first — your code never leaves your browser.

100% FreeNo Sign-upRuns in BrowserPrivacy First

Input JavaScript498 B

Minified Output

Why Minify JavaScript?

JavaScript minification is the process of removing all characters from source code that are not required for execution — comments, whitespace, newlines, and sometimes variable name shortening. The resulting file is functionally identical to the original but significantly smaller.

For web performance, every kilobyte matters. Browsers must download, parse, and compile JavaScript before a page becomes interactive. Reducing JS payload directly improves Time to Interactive (TTI) and First Contentful Paint (FCP) — both of which Google uses as Core Web Vitals signals that affect SEO rankings.

Real-World Impact

A typical React or Vue application before build tooling can be 200–500 KB of raw source. After minification, that same bundle often drops to 80–150 KB — a 40–70% reduction. When combined with Gzip or Brotli compression (which works even better on already-minified text), final transfer sizes can be as low as 25–40 KB.

What Gets Removed?

•Block comments: /* This entire block is stripped */
•Line comments: // These are removed too
•Unnecessary spaces: if ( x === 1 ) → if(x===1)
•Newlines and tabs: Multi-line code collapsed to one line
•Trailing commas: In some engines (optional step)

Minification vs. Obfuscation: What's the Difference?

Minification

Minification removes whitespace and comments — that's it. The resulting code is still fully readable when reformatted, and variable names like calculateTax remain as-is. Source maps can be generated alongside the minified file to allow debugging in browser DevTools with the original formatting restored. Minification is purely a performance optimisation.

Obfuscation

Obfuscation goes further — it renames variables to meaningless short names (a, b1, _0x3f), converts strings to hex encoding, and inserts dead code — making reverse engineering intentionally difficult. Unlike minification, obfuscation provides a mild security layer at the cost of slightly larger file sizes and reduced debuggability.

Which Should You Use?

For most web projects, minification alone is the right choice — it gives maximum performance benefit with no trade-offs. Use obfuscation only when protecting proprietary business logic from inspection is a hard requirement, such as in licensed SDK code or anti-cheat systems for browser games.

When to Minify Manually vs. Using a Build Tool

Production build tools like Vite, webpack, and Next.js automatically minify JavaScript during a production build using Terser or esbuild. You should use this tool when:

•You have a standalone script (.js file) not part of a build pipeline
•You want to quickly check how much a specific snippet can be reduced
•You need to minify a config or data file for embedding in HTML
•You are comparing the output of different minification strategies
•You are generating a one-off bookmarklet or userscript

FAQ

Is minified JavaScript safe to deploy directly?

Yes, for simple scripts. For complex applications, always test the minified output before deploying — our tool preserves string literals and regex safely, but very complex or unusual syntax patterns are best handled by a full build tool like Terser or esbuild in your CI pipeline.

Why does the minifier preserve /*! comments?

Comments starting with /*! (a bang) are convention for licence notices (e.g. jQuery's MIT licence header). Many projects are legally required to keep them in the distributed build. Our minifier detects the ! prefix and preserves those blocks.

Does minification break regular expressions in my code?

Our tool uses a character-level tokenizer that detects regex literals using context (what token preceded the /) and reads them character by character including character classes and escape sequences. Regex literals are treated as protected regions — their content is never altered.