JSON validator
Find out instantly whether your JSON is valid — and exactly what’s wrong if it isn’t.
Free No sign-up Runs in your browser
How it works
How to use the JSON Validator tool
- 1
Paste JSON
Or open a .json file.
- 2
Read the verdict
Valid JSON is confirmed; errors show line, column and a clear explanation.
- 3
Fix and format
Jump to the error, fix it, and copy formatted output.
Errors explained
Common mistakes — trailing commas, single quotes, unquoted keys, comments, missing brackets — are recognised and explained, not just reported as “Unexpected token”.
Limitations
We’d rather be upfront about what this tool can’t do yet:
- Validates JSON syntax, not against a JSON Schema.
- JSON5 and comments are reported as invalid (they aren’t standard JSON).
FAQ
Frequently asked questions
Is my data sent anywhere?
No. All processing happens locally in your browser. Nothing you enter is uploaded, stored or logged.
Does it validate against a schema?
Not yet — it checks that the document is syntactically valid JSON.
Keep going