JSON Formatter & Validator
Format, validate and minify JSON online. Pretty-print with 2 or 4 spaces, sort keys, get exact error line on invalid JSON. Free, 100% client-side.
Input · json0 chars
Output · json0 chars
🔒 100% private: this tool runs entirely in your browser. Your data is never uploaded, stored or logged anywhere.
How to json formatter
- Paste JSON — formatted output appears instantly.
- Invalid JSON? You get the exact line number of the error.
- Switch between pretty (2/4 spaces) and minified output.
FAQ
Does formatting change my data?
Never — only whitespace and key order (if you enable sorting). Values are untouched.
How precise is the error message?
The parser reports the message from the JSON engine plus the computed line number of the failure point.
Can it handle large files?
Yes, comfortably up to several MB — limited mainly by your device memory, since everything runs locally.