Free Online JavaScript Formatter & Beautifier
Paste JavaScript above and click Beautify to re-indent brace-structured code, Minify to strip comments and compress whitespace, or Validate to run a syntax check that reports errors without ever executing your code. Everything happens locally — snippets, bookmarklets and proprietary code stay on your machine.
What this tool is for
- Reading minified code — expand a compressed snippet from a website or library enough to follow its structure.
- Cleaning up pasted snippets — code from chat messages, PDFs and docs arrives with mangled indentation.
- Bookmarklets — minify a script into the single line a bookmarklet requires.
- Quick syntax checks — confirm a snippet parses before dropping it into a page, with the error name and message if it does not.
How the syntax check works — without running your code
Validation uses the JavaScript engine's own parser via the Function constructor: your code is parsed but never invoked, so nothing executes, no network requests fire and no side effects occur. If parsing fails, you get the engine's real error message — the same one you would see in the console. One limitation: top-level import/export statements are module syntax and will be reported as errors even though they are valid in a module file.
An honest note on scope
This is a fast structural indenter, ideal for snippets and everyday cleanup. It is not a full code-style engine like Prettier — it will not rewrap long lines, normalise quotes or enforce a style guide. For whole codebases, use Prettier or ESLint in your build; for the snippet in front of you right now, this is quicker.
Frequently asked questions
Is my code executed?
No. Beautify and minify are pure text transforms; validation parses without invoking.
Does minification rename my variables?
No — this is safe whitespace-and-comment minification, not obfuscation. Names, strings and logic are untouched, so the output is guaranteed to behave identically.
Does it support TypeScript or JSX?
Beautify generally handles them since both are brace-structured, but validation checks standard JavaScript syntax only.