JSON formatter and validator
Format, validate, beautify or minify JSON. Errors are pinpointed, and everything stays in your browser.
Runs 100% in your browserHow to format JSON
- Paste your JSON. Paste or type JSON into the input box.
- Choose formatting. Pick an indent size, minify, or sort keys; the output updates live.
- Copy or download. Grab the formatted result with Copy or Download.
About JSON formatting
JSON is the lingua franca of web APIs, config files and logs, but minified or hand-edited JSON is hard to read and easy to break. A formatter re-indents it consistently so structure is obvious, and validation catches the usual culprits — trailing commas, single quotes, unquoted keys, missing brackets. Minifying does the reverse for production payloads. This tool uses the browser's strict, standards-compliant parser, so what it accepts is exactly what your APIs will.
Frequently asked questions
- It validates your JSON and pretty-prints it with consistent indentation, or minifies it to a single line. Invalid JSON is reported with a clear message and the position of the error.
- It won't silently guess, but it pinpoints the first syntax error (e.g. a trailing comma or single quotes) so you can fix it. Strict, standards-compliant JSON only.
- It runs in your browser, so very large documents (tens of MB) may be slow depending on your device, but there is no server limit and nothing is uploaded.
- Yes. Parsing and formatting use the browser's native JSON engine locally. Your data is never sent anywhere.