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JSON Formatter & Validator

Pretty-print and validate JSON, with clear error messages.

JSON

✓ Valid JSON

StatusValid

Formatted length99 chars

{
  "name": "UtilGears",
  "tools": 81,
  "free": true,
  "tags": [
    "fast",
    "private"
  ]
}

Paste minified or messy JSON to format it with clean 2-space indentation — or get a clear error if it is invalid. A fast, private way to read and check JSON, right in your browser.

Formula / method

parse the input, then re-print it with 2-space indentation

Examples

{"a":1,"b":[2,3]}
formatted with indentation

{a:1}
Invalid JSON (keys need quotes)

Format and validate in one step

Minified or messy JSON is hard to read and easy to break. This tool re-indents JSON into a clean, nested layout and, in doing so, validates it — if the text is not valid JSON, parsing fails and you know there is a syntax error to fix, such as a trailing comma or an unquoted key.

Private by design

Formatting happens entirely in your browser, so configuration files, API responses and any data you paste are never uploaded to a server. That makes it safe to use with payloads that contain tokens or personal information. To learn the format itself, see the What Is JSON guide.

Where it's used

Pretty-printing a minified API response so its structure is readable
Validating that a config file or payload is syntactically correct JSON
Reformatting compact JSON copied out of browser dev tools or a log line
Indenting a package.json, tsconfig, or app manifest before committing it
Spotting a misplaced comma or unclosed bracket in hand-edited JSON

Real-world examples

A developer pastes a one-line API response and gets it indented so they can trace a nested user.address.city field.
A minified webhook payload pulled from a log is expanded to confirm its status and items[] fields.
A config with a trailing comma is caught immediately as a syntax error before it ships.

A bit of history

JSON (JavaScript Object Notation) was specified and popularised by Douglas Crockford in the early 2000s, drawing on JavaScript's object-literal syntax. It was later standardised as ECMA-404 (2013) and as the internet standard RFC 8259.

Did you know?

JSON has no syntax for comments — Crockford deliberately left them out to keep the format simple and stop people from smuggling parsing instructions into data files.

FAQ

Is my JSON sent anywhere?

No. Parsing and formatting happen entirely in your browser — nothing is uploaded, so it is safe for sensitive data.