JavaScript Prettify

Paste your JavaScript into the box above and the beautified JavaScript appears instantly below — nothing to press, nothing to upload. It runs entirely in your browser, so it is fast and private, and you can copy the output or download it as a file.

Yes. It is completely free with no signup or limits, and it is private because everything happens locally in your browser — your code is never sent to a server. That makes it safe for proprietary or unreleased code, and it keeps working offline once the page has loaded.

It re-indents and formats your JavaScript into clean, readable code with consistent spacing. Readable, consistently-formatted code is easier to review and maintain.

No — only the formatting changes; the code itself does exactly what it did before. You get the same functionality with cleaner, more readable output.

There is no fixed limit because nothing is uploaded — the only constraint is your device's memory, so even large files process quickly on a normal computer. The engine loads on first use and is cached afterwards, so repeat runs are instant.

Yes. It runs in any modern browser on Windows, Mac, Linux, iPhone and Android with nothing to install, and works offline once loaded. The result can be copied or downloaded on any device.