JSON Validator
Check whether JSON is valid and see the exact syntax error if it isn't.
Audit Metrics
Paste JSON and this tool tells you immediately whether it's valid — and if it isn't, it shows the exact error so you can find the problem. It uses the browser's own JSON parser, the same engine your code runs against, so a “valid” result here means it will parse in JavaScript too. When the JSON is good, it also reports the root type and the size. Everything runs in your browser; nothing is uploaded.
Valid or invalid, with the real error
Validation runs through JSON.parse(). If it succeeds, you get a clear “valid” state; if it fails, the tool surfaces the parser's own message — things like “Unexpected token” or “Unexpected end of JSON input” — which point you at the trailing comma, missing quote or unclosed bracket that broke it. Because this is the native parser, the verdict is authoritative rather than a best guess.
Type and size at a glance
For valid input the tool reports the root type — whether your JSON is an Array, an object, a string, a number, and so on — which is a quick way to confirm the shape is what you expected. It also shows the size in kilobytes, useful when you're checking a payload against an API limit. Note that this tool checks syntax, not meaning: it confirms the JSON is well-formed, not that it matches a particular schema or contains the fields your application needs.
Frequently Asked Questions
What does the error message tell me?
It is the browser's own JSON.parse error, such as "Unexpected token" or "Unexpected end of JSON input". These pinpoint the kind of problem — a stray comma, missing quote or unclosed bracket — so you can locate it.
Does it check my JSON against a schema?
No. It validates syntax only — whether the text is well-formed JSON. It does not verify that required fields exist or that values match a schema. For that you would use a JSON Schema validator.
What does the "type" result mean?
It is the root value's type: Array, object, string, number, boolean or null. It helps you confirm the top-level shape — for instance that you received an array rather than a single object.
Is my data sent to a server?
No. Validation happens entirely in your browser via the native JSON parser, so nothing you paste leaves your device.