Format, beautify & validate JSON instantly.
The JSON Formatter and Validator instantly beautifies minified JSON into readable indented output and catches syntax errors with precise line-number feedback. Paste raw API responses, config files, or log data and get clean, colour-highlighted JSON in one click — no sign-up, no data sent to a server, fully client-side.
Formatting (also called prettifying) re-indents and adds whitespace to make JSON human-readable without changing its meaning. Validating checks that the JSON follows the specification — catching issues like trailing commas, unquoted keys, or mismatched brackets that would cause a parse error in code.
Common culprits are trailing commas after the last item in an array or object (not allowed in JSON, though permitted in JavaScript), single-quoted strings instead of double-quoted, and JavaScript-style comments. The formatter highlights the exact line of the error to help you find it quickly.
Yes. The minify option strips all unnecessary whitespace to produce the most compact representation — useful when you need to reduce payload size in an API request or store JSON in an environment variable.
All processing happens in your browser using JavaScript. No data is transmitted to any server, so pasting API keys, tokens, or internal config values does not expose them to third parties.