What is JavaScript minification?
JavaScript minification removes unnecessary whitespace, comments, and punctuation where safe so source code becomes smaller for transport or storage.
JavaScript Minifier
Reduce JavaScript size by minifying code locally in your browser and reviewing the size savings.
JavaScript input
Paste functions, modules, async flows, classes, or verbose browser code.
JavaScript is never executed. Minification parses source text only. Review output before replacing production bundles.
Minified JavaScript
Compact output with syntax feedback and byte savings.
Ready to minify JavaScript
Paste JavaScript or load a sample, then minify to check syntax and review size savings.
Modules, classes, async/await, optional chaining, and template literals are supported as source text.JavaScript Minification Guide
Compact JavaScript locally without executing code
Minify functions, modules, snippets, and pasted application code as inert source text, then compare the original and minified byte counts.
JavaScript Minifier vs Formatter
A formatter expands JavaScript for review and debugging. A minifier compacts JavaScript for smaller output after code is already understood and tested.
How size savings are calculated
The summary compares browser byte counts for the original source and minified output, then reports saved bytes and percentage reduction.
Safe vs aggressive minification
Conservative compression rewrites simple expressions. Aggressive options such as name mangling can be useful, but they should stay opt-in and test-backed.
Comments and licensing
Comments are removed by default for compact output. Enable preservation when license banners or important release notes must remain in the result.
Modern JavaScript support
Modules, classes, async/await, arrow functions, destructuring, optional chaining, nullish coalescing, and template literals are parsed as source text.
JavaScript Minifier FAQ
Does this JavaScript Minifier execute my code?
No. The tool treats input as text, parses it with the minifier, and never uses eval, Function, script injection, live preview, or runtime imports from your code.
Can I use this instead of a bundler?
Use it for snippets, quick checks, and standalone files. Production applications should still use their build pipeline for bundling, tree shaking, source maps, and testing.
What is the difference between compressing and mangling?
Compression rewrites expressions to smaller equivalents. Mangling renames supported identifiers to shorter names and is more aggressive, so it is off by default.
Will comments be removed?
Yes, comments are removed by default. Turn on Preserve comments when license-style comments should remain in the minified output.
Why did minification fail?
Syntax errors, incomplete snippets, unsupported parser features, and broken strings or template literals can stop minification until the input is corrected.
Does this tool upload my JavaScript?
No. Minification, syntax checks, copying, and downloads run locally in your browser.