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A JSON object, array, string, number, or literal.
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JSON formatter & validator
Find syntax errors quickly and produce clean, copy-ready JSON.
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Formatted JSON
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What does json formatter & validator do?
Parse a JSON value to verify its syntax, then serialize it with one, two, or four spaces of indentation or with no optional whitespace. Valid top-level arrays, strings, numbers, booleans, and null are accepted as well as objects.
- Input
- A JSON object, array, string, number, or literal.
- Result
- Formatted or minified JSON plus validation feedback.
- Price
- Free
- Account
- Not required
How to use json formatter & validator
Choose your settings
Find syntax errors quickly and produce clean, copy-ready JSON.
Save or copy
Formatted or minified JSON plus validation feedback.
A practical tip
JSON requires double-quoted property names and does not permit trailing commas.
When to use json formatter & validator
Pretty-print a compact API response before reading nested fields.
Validate a configuration fragment and surface the browser parser's syntax error.
Minify a hand-edited JSON fixture before embedding or transport.
Worked example
A concrete json formatter & validator example
- Input
- {"project":"TinyFreeTools","tools":["color","pdf"]}
- Settings
- Format with 2 spaces
- Result
- The result is a multi-line object with project set to TinyFreeTools and tools formatted as a two-item indented array. Minify returns the original compact structure without optional spaces.
What to expect
How it works
The page passes the entire input to JavaScript JSON.parse(). When parsing succeeds, JSON.stringify() serializes the resulting value with the selected indentation or zero indentation. A parse exception is displayed instead of producing partial output.
Know before using
Limits and edge cases
- JavaScript numbers cannot exactly represent every integer beyond Number.MAX_SAFE_INTEGER, so parsing and reserializing very large numeric IDs can change them.
- Comments, trailing commas, single-quoted strings, NaN, Infinity, and duplicate-key history are not preserved; this is strict JSON rather than JSON5 or a lossless editor.
Standards and sources
Common questions
JSON formatter & validator FAQ
Is json formatter & validator free to use?
Yes. JSON formatter & validator is free to use.
Does json formatter & validator keep my work private?
Yes. Your work stays private while you use the tool — nothing you enter is uploaded.
Why does a trailing comma produce an error?
Trailing commas are permitted in some JavaScript literals but not in the JSON grammar. Remove the comma after the final member or array item.
Can the formatter safely round-trip a 20-digit integer?
Not reliably. JSON.parse() stores it as a JavaScript Number, which may lose integer precision. Quote identifier-like large integers or use a lossless JSON parser when exact numeric text matters.