JSON Validator

Check whether JSON is valid and see exactly where a syntax error is, by line and column, plus structure statistics for valid JSON.

What is the JSON Validator?

A JSON validator confirms that text follows the JSON specification (RFC 8259) so it can be parsed by any program.

How does it work?

The input is parsed strictly. On failure, the parser’s error position is converted to a line and column. On success, the tool counts objects, arrays, keys and nesting depth.

Example

A trailing comma in ["a", "b",] is reported as an error on the line where it appears.

Frequently asked questions

Is my data sent to a server?

No. This tool runs entirely in your browser; nothing you paste is uploaded or stored.

Why is my JSON invalid?

Common causes are trailing commas, single quotes instead of double quotes, unquoted keys, comments, and NaN or undefined values — none of which are allowed in JSON.

Related tools

Enable JavaScript to use this calculator.