Beautify, minify and validate JSON online — free, fast, private.
What is a JSON formatter?
A JSON formatter takes raw or minified JSON (JavaScript Object Notation) and rewrites it with
consistent indentation and line breaks so it is easy for humans to read. This tool also validates
your input: if the JSON is invalid, you get a clear error message with the exact line and column
where parsing failed.
How to use this tool
- Paste your JSON into the input box above.
- Click Format / Beautify to pretty-print it, or Minify to remove all whitespace.
- Use Validate to check syntax without changing the text.
- Copy the result with one click.
Why format JSON?
- Debugging: APIs often return minified JSON that is impossible to scan. Indentation makes structure visible.
- Error detection: a missing comma or quote breaks parsing — the validator pinpoints it.
- Privacy: everything runs locally in your browser. Your data is never uploaded to a server.
What formatting changes — and what it leaves alone
Format / Beautify runs your input through a real JSON parser and rewrites it, so the output is always syntactically valid. That round-trip normalizes a few things worth knowing about:
| Input | After formatting | Why |
|---|
1e3 | 1000 | Exponential notation becomes a plain decimal. |
1.50 | 1.5 | Insignificant trailing zeros are dropped. |
{"b":1,"a":2} | {"b":1,"a":2} | String keys keep their original order. |
{"2":"x","1":"y"} | {"1":"y","2":"x"} | Integer-like keys are re-sorted ascending. |
9007199254740993 | 9007199254740992 | Integers above 2^53 - 1 lose precision. |
Pro tips
- Hunting a syntax error? Click Validate first — the status line reports the exact line and column of the first failure, so fix the input before reformatting it.
- Tick 4 spaces when pasting JSON into documentation or pull requests; the wider indent reads better outside an editor.
- Minify before embedding JSON in code or URLs: the Sample data shrinks from 118 characters formatted to 77 minified.
- Store long IDs as quoted strings if every digit matters — quoting protects them from the number round-trip shown above.
Frequently asked questions
Is this JSON formatter free?
Yes. The tool is completely free, requires no sign-up, and has no usage limits.
Is my JSON data safe here?
Yes. All formatting and validation happens locally in your browser using JavaScript. Your data is never sent to any server.
What JSON errors can the validator detect?
It detects every syntax error that makes JSON.parse fail: missing or extra commas, unquoted keys, trailing commas, single quotes, unclosed brackets, and more — with the line and column of the problem.
Can I minify JSON as well as beautify it?
Yes. Click Minify to strip all insignificant whitespace, producing the smallest valid representation of your JSON.