Developer
JSON Validator
Check whether JSON is valid and get a clear syntax error when it is not.
Common questions
What makes JSON invalid?
Common errors: trailing commas (not allowed in JSON), unquoted keys, single quotes instead of double quotes, comments, unquoted string values, and missing commas between properties. The tool reports the exact error and position.
Does it validate JSON Schema?
No. This tool validates JSON syntax only — it checks whether the structure is valid JSON. For schema validation (checking that specific fields exist with correct types), you would need a dedicated JSON Schema validator.
Is there a file size limit?
There is no artificial limit. The tool processes everything in your browser using JavaScript. Very large files (over 100MB) may be slow depending on your device, but there is no server-side restriction.