JSON Validator

Paste JSON to check whether it is well-formed. Invalid input produces a clear error message with the error position where possible.

JSON input

Press Ctrl+Enter to validate.

What makes JSON invalid?

JSON has a strict grammar. Common mistakes that cause parse errors include:

Trailing commas — e.g. {"a": 1,} (not allowed in JSON, though valid in JavaScript).
Single quotes — JSON requires double-quoted strings.
Unquoted keys — all object keys must be in double quotes.
Comments — JSON does not support // or /* */ comments.
Undefined / NaN / Infinity — these JavaScript values are not valid JSON.

Privacy

Validation uses the browser's native JSON.parse. Your input is never sent to a server.