JSON Validator
- Exact line
- Fix hints
- Nothing uploaded
Find the exact line and column that breaks your JSON, and what to do about it.
About validator
A JSON validator checks whether text parses as valid JSON and reports the first syntax error. JSONic gives the exact line and column, explains the likely cause — an unbalanced bracket, a trailing comma, a single-quoted string — and offers a one-click auto-fix for the common cases.
Paste JSON to check whether it parses. When it does not, JSONic reports the failing line and column and explains the likely cause — an unbalanced bracket, a trailing comma, a single-quoted string — instead of only echoing the raw parser message. When the engine gives no offset, a structural scanner locates the problem instead of blaming the last line. Valid documents get a type histogram and notes on structure worth reconsidering.
Questions
Which JSON specification is used?
The browser's native JSON.parse, which implements RFC 8259. NaN, Infinity, undefined, comments and trailing commas are rejected, exactly as a strict parser would.
Why did another validator report a different line?
Some validators report the offset of the token the parser gave up on, others the start of the construct that failed. JSONic maps the engine's byte offset directly to a line and column, and falls back to its own scanner when the engine reports no offset at all.
Can it validate against a JSON Schema?
Not yet — this checks syntax, not conformance. The schema generator can infer a draft 2020-12 schema from a sample document as a starting point.