JSON Validator
Paste your JSON to instantly check its syntax. Errors are shown with descriptive messages pointing to the exact problem.
JSON to Validate
Real-time Validation
Validates as you type with instant feedback.
Detailed Errors
Shows exact error messages from the JSON parser.
100% Private
No data sent to servers. All processing in browser.
Frequently Asked Questions
What does JSON validation check?
It checks that your JSON strictly conforms to RFC 8259: properly matched braces and brackets, double-quoted keys, valid value types, no trailing commas, and no comments.
Why does my JSON with single quotes fail validation?
Single quotes are not valid JSON. The JSON standard requires all strings (including keys) to be wrapped in double quotes.
Why doesn't JSON allow trailing commas?
The JSON specification (RFC 8259) explicitly disallows trailing commas. JavaScript allows them in objects, but JSON as a data interchange format does not.
Can JSON contain comments?
No. Comments (// or /* */) are not valid JSON. Remove all comments before validating or parsing.