Validate, beautify and minify JSON instantly. All processing happens in your browser — your data never leaves your device.
Formatted JSON will appear here…
Paste any JSON and immediately see if it is valid. Error messages pinpoint the exact line and character where the syntax breaks, so you can fix issues quickly without guessing.
Format compressed or minified JSON into readable indented output with colour-coded keys, strings, numbers, and booleans. Makes complex nested JSON immediately navigable.
Remove all whitespace from a formatted JSON to produce minified output — smaller in size and ideal for embedding in API responses, config files, or network payloads.
Valid JSON (JavaScript Object Notation) must: use double quotes for strings (not single quotes), have all keys in double quotes, not contain trailing commas after the last item in an array or object, and be either a JSON object {}, array [], string, number, boolean, or null at the top level.
Common JSON errors include: single quotes instead of double quotes, trailing commas (JSON does not allow them), undefined or NaN values (not valid JSON), JavaScript comments (// or /* */), unescaped special characters in strings, and missing commas between object properties.
JavaScript objects allow single quotes, trailing commas, comments, function values, undefined, and unquoted keys. JSON is a strict subset — all keys must be double-quoted strings, no trailing commas, no comments, and only numbers, strings, booleans, null, arrays, and objects are valid value types.