JSON Validator
Check whether a block of JSON is syntactically valid.
This JSON Validator checks whether pasted or uploaded JSON is syntactically valid, entirely in your browser. If the JSON is invalid, it reports the exact line and column where parsing failed, when the parser can determine one. It only reports problems — it won't guess a fix or rewrite the JSON for you.
How to use
- 1Paste JSON into the input, or upload a .json file.
- 2Click Validate.
- 3If the JSON is invalid, the exact line and column of the problem are shown when available.
Frequently asked questions
What does a JSON validator check?
It checks that the text follows JSON's grammar rules exactly — matched brackets and quotes, correctly separated key-value pairs, no trailing commas — the same rules a strict JSON.parse() call would enforce.
Why would I validate JSON before using it?
Invalid JSON typically causes a cryptic parse error deep inside whatever code consumes it. Validating first, with a clear line/column pointer, is faster than debugging that failure after the fact.
Does this fix invalid JSON for me?
No — it tells you the JSON is invalid, why, and where, but won't guess your intended fix.
Is my JSON uploaded anywhere?
No. Validation runs entirely client-side in your browser tab — nothing is sent over the network.