JSON Formatter & Validator
Beautify, minify and validate JSON in your browser. Choose your indentation, catch syntax errors, and copy clean output.
What is a JSON formatter?
JSON is the lingua franca of APIs and config files, but it's often delivered minified or pasted as an unreadable single line. A formatter parses it and prints it back with tidy indentation so you can actually read the structure. Because it parses first, it doubles as a validator — if your JSON has a syntax error, you'll know immediately and see the message. Everything runs locally with the browser's native JSON engine.
Format vs minify
- Format — expand with indentation for reading and debugging.
- Minify — collapse to the smallest valid form for transport.
- Validate — instantly confirm the JSON is well-formed.
How to use it
- 1Paste your JSON into the input box.
- 2Click Format to beautify, or Minify to compact it.
- 3Choose your preferred indentation width.
- 4Copy the clean output, or fix any reported errors.
Frequently asked questions
What does the JSON formatter do?+
It parses your JSON and re-serializes it with clean, consistent indentation (2 spaces, 4 spaces or tabs). If the JSON is invalid, it tells you exactly what went wrong so you can fix it.
How does minify differ from format?+
Format (beautify) adds whitespace and line breaks for readability. Minify strips all optional whitespace to produce the smallest valid JSON, which is what you want for API payloads and production configs.
Why is my JSON invalid?+
Common causes are trailing commas, single quotes instead of double quotes, unquoted keys, or comments — none of which are allowed in strict JSON. The validator reports the parser's error message to help you locate the problem.
Is my JSON sent to a server?+
No. Parsing, formatting and validation all happen locally in your browser using the native JSON parser. Your data never leaves your device.