JSON Formatter
Formatting and validating JSON
Paste JSON to validate its syntax, format it with readable indentation, or minify it for transport. Processing happens in your browser, so the text is not sent to this site.
Formula and method
Valid JSON requires double-quoted property names and strings, supported literal values, and correctly balanced arrays and objects.
Worked example
The input {"ok":true} formats across multiple indented lines while preserving the same data.
How to interpret the result
Successful formatting confirms that the text can be parsed as JSON; it does not prove the data follows an application's schema. The formatter changes whitespace, not the represented values. Minification is useful for transport, while indentation is better for review and debugging.
Important limitations
- Comments and trailing commas are not valid JSON.
- Avoid pasting secrets into any browser tool on an untrusted device.
Common questions
Why are comments and trailing commas rejected?
They are accepted by some programming-language extensions but are not part of the JSON grammar. Removing them improves interoperability with strict parsers.
Can formatting change large numbers?
JavaScript parses JSON numbers as double-precision values. Extremely large integers can lose precision if parsed and serialized, so represent identifiers as strings when every digit must be preserved.
Related tools
Method and examples reviewed September 8, 2026.