JSON Formatter & Validator
Paste JSON, get it back clean and validated. Beautify or minify, sort keys, and when something's wrong, see exactly where — line, column, and a caret pointing at the problem. Everything runs in your browser; nothing is uploaded.
What this validates
This tool checks your input against the JSON specification (RFC 8259) — the same rules every parser enforces. It uses a hand-written parser rather than the browser's built-in JSON.parse, which lets it report the exact line and column of the first error in every browser. Safari's native parser, for instance, often won't tell you where a problem is; this one always will.
The mistakes it catches
The most common JSON errors are simple and avoidable once you can see them: trailing commas (valid in JavaScript, forbidden in JSON), single quotes instead of double quotes, unquoted keys, missing commas between items, unterminated strings, and comments (JSON has none). For each, the tool shows a plain-language message and a caret pointing at the offending character.
Format, minify, sort
Format pretty-prints with your chosen indent (2 spaces, 4 spaces, or tabs) so structure is readable. Minify strips all insignificant whitespace for the smallest possible payload — useful before sending JSON over the wire. Sort keys alphabetises object keys recursively, which makes diffing two JSON files far easier and produces deterministic output.
Privacy
Everything happens in your browser. Your JSON is never sent to a server, logged, or stored. You can disconnect from the network and this page will keep working — paste a config file or an API response with confidence that it stays on your machine.