Dev-data · Free

JSON Validator — Find Errors with Exact Line and Column

Check whether your JSON is valid and get the exact line and column of the first error with a plain-English reason — in your browser, nothing uploaded.

Stays on your deviceFree
Paste some JSON to format, validate or minify it.

Everything ran in your browser — your JSON was never uploaded.

JSON Validator checks whether your JSON is well-formed and tells you exactly what’s wrong when it isn’t — in your browser, with nothing uploaded. Paste a payload that an API rejected or a config file that won’t load, and you’ll see a clear verdict plus the precise line and column of the first error, with a plain-English reason: a trailing comma, a single-quoted key, a missing comma, an unterminated string. Because a missing comma is usually reported on the line after the real mistake, the validator reminds you to check the line above — the single most common gotcha when debugging JSON. No account, no upload, no waiting.

FAQ

How it works & more

JSON Validator checks whether your JSON is well-formed and tells you exactly what’s wrong when it isn’t — in your browser, with nothing uploaded. Paste a payload that an API rejected or a config file that won’t load, and you’ll see a clear verdict plus the precise line and column of the first error, with a plain-English reason: a trailing comma, a single-quoted key, a missing comma, an unterminated string. Because a missing comma is usually reported on the line after the real mistake, the validator reminds you to check the line above — the single most common gotcha when debugging JSON. No account, no upload, no waiting.

FAQ