JSON Formatter & Validator
Beautify, minify and validate JSON with clear, positioned error messages. Fast, private and entirely client-side.
Runs locally · nothing uploaded Input
Output
Formatted JSON will appear here.
About JSON formatting
JSON (JavaScript Object Notation) is the most common data-interchange format on the web. This tool pretty-prints minified JSON so it’s readable, minifies it to save bytes, and validates structure so you can catch syntax errors before they reach production. Everything runs with your browser’s native parser — no upload, no waiting.
Frequently asked questions
Is my JSON sent to a server?
No. All parsing and formatting happens in your browser with the native
JSON engine. Your data never leaves your device.What does the validator catch?
Any syntax error — trailing commas, unquoted keys, single quotes, missing brackets — with the exact position so you can fix it quickly.
Can it handle large files?
Yes, formatting runs locally so it’s limited only by your browser’s memory. Very large documents (tens of MB) may take a moment.