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Validate JSON instantly and see exactly where the syntax error is.
A JSON validator checks whether text is syntactically valid JSON and tells you exactly where it breaks. Catching a stray comma or a missing quote here saves a debugging round trip once the payload reaches your code.
Validation happens locally in your browser. Nothing is transmitted, and the result appears as you type, so you can check secrets, environment files, and private records with confidence.
Valid object
Input
{"name":"Ada","age":36}Output
Valid JSON - parsed successfully.Column numbers count from 1 at the first character of each line.
Trailing comma
Input
{"name":"Ada","age":36,}Output
Invalid JSON: unexpected } at line 1, column 24 (trailing commas are not allowed).The trailing comma sits at position 23, so the parser trips on the closing brace that follows.
Missing comma between properties
Input
{"a":1
"b":2}Output
Invalid JSON: unexpected string at line 2, column 1 (expected , or }).Multi-line documents are reported with the line number where parsing stopped.
It checks syntax only: whether the text parses as JSON. Validating keys and value types against a schema is a separate step.
No. The tool validates strict JSON as defined by the standard, which does not allow comments, trailing commas, or unquoted keys.
No. Parsing happens in your browser, so the text you check never leaves your device.
The usual culprits are a trailing comma, smart quotes copied from a document, or a stray comment. The reported line and column shows which one it is.
Paste or type JSON — it's checked as you type.