js-formatter // v1
Paste messy JavaScript or JSON, get clean, readable code back in milliseconds. No signup, no upload — formatting runs entirely in your browser.
Most online formatters stop at "beautify." This one bundles the features developers actually reach for, so you rarely need to switch tabs.
Formats JavaScript and JSON in real time using Prettier's rules — consistent output every time.
Strip comments and whitespace to shrink file size before you ship, without leaving the page.
Paste JSON or JavaScript and the tool figures out which one it's looking at.
Switch between 2 spaces, 4 spaces or tabs to match your team's style guide.
Toggle single vs double quotes and whether semicolons are added or stripped.
If your code won't parse, you get a clear error message instead of a silent failure.
Grab the formatted result with one click, or download it straight as a .js or .json file.
See input and output size at a glance — handy for spotting bloated code.
Hit Ctrl / Cmd + Enter to format without touching the mouse.
No account, no rate limits, no watermark. Use it as many times as you need.
Your code never leaves your browser — there's no server call to send it to.
The full tool is usable on a phone screen, not just a cut-down version.
Three steps, no installation required.
Drop your JavaScript or JSON into the input panel above.
Pick indent size, quote style and semicolon handling, or leave the defaults.
Click Format, then copy or download the clean result.
Inconsistent spacing, mixed quote styles and missing semicolons don't break your code, but they slow down everyone who has to read it — including you, six months from now. A formatter removes that decision entirely: it applies one consistent style to every file, so code reviews focus on logic instead of nitpicking commas and indentation.
This matters even more on teams. When every contributor's editor is configured slightly differently, diffs get noisy — a one-line change turns into a fifty-line diff because someone's editor re-indented the whole file. Running code through a shared formatter before committing keeps diffs small and reviews fast.
If you're new to this, our guide on what JavaScript formatting actually does is a good starting point, and our comparison of Prettier vs JS Beautify explains why this tool is built on Prettier's rules specifically.
Guides on formatting, style guides and tooling for JavaScript developers.
The basics of code formatting, explained for developers who've never thought about it.
Two popular formatters compared on rules, configuration and ecosystem support.
The small style issues that quietly make code reviews harder than they need to be.
When to compress your code and when to keep it readable.
Yes. The formatter, minifier and JSON validator are completely free with no signup, no account and no usage limits.
No. Formatting and minifying happen entirely in your browser. Nothing you paste is sent to any server or third-party API — see how this is possible in our guide on setting up Prettier locally.
Yes. Switch the language selector to JSON, or leave it on Auto-detect. Read more in how to format JSON online.
The beautifier is built on Prettier's rules. You can adjust indent size, quote style and semicolons to match your own style guide — see how popular guides differ in Airbnb vs Google vs StandardJS.
No — they solve different problems. Formatting is about layout; linting is about catching bugs and enforcing patterns. See ESLint vs Prettier: Do You Need Both?