JSON Formatter & Validator

Paste JSON to instantly format, validate, and explore it. Pinpoint errors by line and column, browse an interactive tree, sort keys, and minify — all in your browser.

100% client-side. Your JSON never leaves your device.
Awaiting input
Input
Output
Formatted JSON will appear here.

About the JSON Formatter & Validator

JSON is everywhere — API responses, config files, log lines, exports — and it's unforgiving about a single misplaced comma. This tool takes messy, minified, or broken JSON and makes it readable in an instant: it pretty-prints with the indentation you choose, validates against the JSON spec, and tells you exactly where a problem is by line and column. Switch to the tree view to fold large structures down to the parts you care about.

It all runs in your browser. Your JSON is never uploaded, never logged, and never sent anywhere — which matters, because that payload you're debugging might contain API keys, tokens, or customer data you'd rather not paste into a random website.

What it does

Common uses

Good to know

No account, no upload, no nonsense — paste, read, fix, ship.

Common questions

How do I format messy JSON?

Paste it and it beautifies instantly with proper indentation. The collapsible tree view makes deeply nested structures navigable, and key sorting tames objects assembled in random order.

How do I find the error in invalid JSON?

The validator pinpoints the exact line and column where parsing fails, with the usual suspects being a trailing comma, a missing quote, or a single quote where JSON demands double. Fix, revalidate, done.

Is it safe to paste API responses with real data into a JSON formatter?

Into this one, yes: formatting runs entirely in your browser and nothing you paste travels over the network. Pasting production payloads into server-side formatter sites is how customer data ends up in someone's logs; this is the version your security team would ask you to use.

Can I minify JSON as well as beautify it?

Yes. One click strips all whitespace back out for shipping, and the same view can copy or download either version.

Is there a size limit on the JSON I can format?

No artificial one. Your machine does the parsing, so files far larger than most online formatters accept open fine, with the tree view keeping them navigable.

Related tools