Free JSON Formatter & Validator
Something not working? Report a problem
About the JSON Formatter
Pretty-print, minify and validate JSON with the exact line and column of any error — formatted instantly in your browser, nothing is uploaded.
How to use the JSON Formatter
- 1Paste your JSON on the left.
- 2Pick Pretty to format it (choose your indent) or Minify to strip whitespace.
- 3If the JSON is invalid, the exact line and column of the error is shown.
- 4Click Copy to grab the result.
Frequently asked questions
Is my JSON uploaded anywhere?
No — parsing and formatting happen entirely in your browser, so it's safe to paste API responses containing real data.
How do I find the error in my JSON?
Paste it and the validator reports the exact line and column of the first problem, with the parser's message. Fix it and the formatted output appears immediately.
What are the most common JSON mistakes?
Trailing commas after the last item, single quotes instead of double quotes, unquoted keys, and comments — JSON allows none of these, even though JavaScript does.
Does formatting change my data?
Only the whitespace. Values, key order and structure are preserved exactly — pretty and minified versions parse to identical data.
Is there a size limit?
No hard limit — it comfortably handles multi-megabyte API responses, since everything runs locally in your browser's memory.