JSON Formatter & Validator
Paste JSON below to format, validate, and minify it. Everything happens in your browser — open your dev tools' network tab and confirm nothing is transmitted while you use this page.
Batch mode
Why format JSON in the browser?
Most JSON formatters online submit whatever you paste to a remote server for processing. If that JSON contains a real API response, an internal config, or a customer record, that data now lives in someone else's request logs. This tool parses and re-serializes JSON using your browser's own JavaScript engine — the same one already loaded to render this page — so there is nothing to send anywhere.
It also catches common mistakes — trailing commas, unquoted keys, mismatched brackets — and tells you roughly which line the problem is on, instead of just failing silently.