Paste JSON and instantly validate, format (beautify) or minify it — with syntax highlighting and precise error messages showing the exact line and position. Everything runs in your browser; your data never leaves your device.
Your formatted JSON will appear here.
🔒 100% private — formatting happens locally in your browser with JavaScript. Nothing is uploaded anywhere.
What is JSON formatting?
JSON (JavaScript Object Notation) is the standard data format for APIs, configs and web apps. Formatting (beautifying) adds indentation and line breaks so humans can read it; minifying strips all unnecessary whitespace so it is as small as possible for sending over the network. Validating checks that the JSON follows the strict JSON rules — for example, keys must be in double quotes and trailing commas are not allowed.
Common JSON errors this tool catches
Single quotes instead of double quotes: {'a':1} → must be {"a":1}
Trailing commas:{"a":1,} → remove the last comma
Unquoted keys:{a:1} → must be {"a":1}
Comments — plain JSON does not allow // comments
Frequently asked questions
How do I format JSON online?
Paste your JSON into the box above and click Format — the tool validates it first, then pretty-prints it with indentation and syntax highlighting. If the JSON is invalid, you get the exact line and position of the error.
What is the difference between formatting and minifying JSON?
Formatting (beautifying) adds indentation and line breaks so humans can read the JSON. Minifying removes all unnecessary whitespace so the JSON is as small as possible for sending over the network. Both represent the same data.
Is my JSON data safe here?
Yes. Everything runs locally in your browser with JavaScript — your JSON is never uploaded to any server.