JSON Validator
Instantly validate any JSON string and get precise error messages with exact line and column numbers. Also shows JSON structure statistics.
JSON validation checks that your data conforms to RFC 8259 — matching brackets, correct comma placement, valid string escaping, and no trailing commas. This tool gives you the exact line and column of any error, so you can fix it immediately.
Press ⌘Enter to validate
Frequently Asked Questions
What errors does the validator catch?
The validator catches all JSON syntax errors including missing commas, unclosed brackets, invalid characters, and trailing commas.
Is my JSON data secure?
Yes. All validation runs in your browser using JavaScript's JSON.parse(). No data is ever sent to a server.
What is the difference between JSON validation and JSON formatting?
Validation checks whether the JSON is syntactically correct. Formatting (pretty-printing) makes valid JSON more readable. If validation fails, formatting is impossible — fix the syntax error first.
Does JSON allow trailing commas?
No. Standard JSON (RFC 8259) does not allow trailing commas. Some tools like JSON5 or JSONC (used in VS Code settings) do support them, but they are not valid JSON.