Format, minify, sort keys, and validate JSON with readable errors. Fully client-side — no account, uploads, or remote storage.
Added Apr 18, 2026 · Updated Apr 29, 2026
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Formats, minifies, and validates JSON. Pretty-print with configurable indentation, minify for compact storage, or validate structure and report the exact line and column of any syntax error.
Adds newlines and 2-space indentation.
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Removes all whitespace.
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All formatting, minifying, and validation happens entirely in your browser using the native JSON.parse() and JSON.stringify() APIs. Nothing is sent to a server.
Formatting adds indentation and newlines to make JSON human-readable. Choose 2 spaces (most common), 4 spaces, or a tab character.
Minifying removes all whitespace to reduce byte size — useful for API responses, localStorage values, and network payloads.
When JSON is invalid, the formatter reports the exact line and column of the error by counting newlines up to the character offset returned by the JavaScript engine. Common errors:
undefined, NaN, or Infinity values (not valid JSON)Input is capped at 1 MB to keep the browser responsive. For larger files, use a local tool like jq.
The formatter reports the exact line and column where the error was found. Common mistakes: missing quotes around keys, trailing commas, using single quotes instead of double quotes.
Formatting adds indentation and newlines to make JSON human-readable. Minifying removes all unnecessary whitespace to reduce file size, which is useful for API responses and storage.