Validate JSON syntax and see clear error messages when parsing fails. Paste API responses, config files, or webhook payloads to confirm they are well-formed before you deploy.
Paste JSON above to validate.
Frequently Asked Questions
How does JSON validation work?
The tool attempts to parse your input with the browser JSON parser. If parsing succeeds, the JSON is syntactically valid.
Does this check schema or business rules?
No. It only validates JSON syntax — brackets, quotes, commas, and value types.
Can I validate large files?
Yes, within browser memory limits. Very large payloads may slow down live validation.
Is my JSON stored anywhere?
No. Validation runs locally in your browser with no uploads.
Is this tool free and does it work on mobile?
Yes on both counts. The JSON Validator on draft21 is completely free with no sign-up required and works on all devices.