How to Format and Validate JSON (Free Online Formatter)
Learn how to format, beautify, and validate JSON in your browser. Common JSON errors explained, plus a free formatter that pretty-prints and minifies instantly.
Unformatted JSON is nearly impossible to read once it gets past a dozen keys. A formatter takes a single-line blob and turns it into the indented, color-coded tree you actually want to debug.
Pretty-print JSON in one click
Paste your JSON into our JSON Formatter & Validator and it instantly indents with 2 spaces, validates the syntax, and reports the exact line and column of any error. Need it minified for production? One toggle removes all whitespace.
Common JSON errors and how to fix them
- Trailing commas — valid in JavaScript, invalid in JSON
- Single quotes — JSON only allows double quotes around keys and strings
- Unquoted keys — every key must be wrapped in double quotes
- Comments — JSON does not support // or /* */ comments
- Unescaped newlines or quotes inside string values
JSON in API debugging workflows
Most APIs return JSON, and many encode payloads in Base64 or wrap them in JWTs. Decode Base64 strings with our Base64 Encoder / Decoder tool and inspect JWT headers and claims with the JWT Decoder.