JSON formatter and validator
Paste JSON to format it, compact it, sort its keys or check it. Errors come with a line, a column and a hint. Numbers keep every digit, so IDs above 2^53 survive a round trip.
Everything runs in your browser. Nothing you paste is sent anywhere or saved: this page is served with a Content Security Policy that stops it from opening connections (connect-src 'none'), and it has no analytics or ads. Open your browser's Network tab to check that no request carries what you paste.
How to use
Paste or drop a file and press Format. Validate checks without changing the text. Sort keys orders every object's keys A to Z, which makes two documents easier to compare by eye; it never reorders arrays.