JSON Validator
Check if JSON is valid and find the exact line and column of any syntax error.
Runs in your browser — your data never leaves your device.
About the JSON Validator
Paste JSON to find out instantly whether it is valid. If it is not, the validator highlights the exact character where parsing failed and shows the surrounding lines, so you can fix it fast.
For valid JSON you also get a quick summary: the top-level type, total number of keys, nesting depth and size.
How to use the JSON Validator
- Paste your JSON or open a .json file.
- Click Validate JSON (or press Ctrl + Enter).
- Green means valid. Red shows the error message, line, column and a highlighted snippet.
- Click Format to beautify valid JSON.
How it works
Validation follows the official JSON standard (RFC 8259):
- Strings and keys must use double quotes.
- No trailing commas after the last item in an object or array.
- No comments,
undefined,NaNor functions. - Numbers cannot have leading zeros (
007) or a leading+.
Examples
{"a": 1,}→ invalid: trailing comma.{'a': 1}→ invalid: single quotes.{"a": [1, 2, 3]}→ valid: object with 1 key, depth 2.
Frequently asked questions
What is the difference between this and the JSON Formatter?
Both use the same engine. The validator focuses on checking and explaining errors; the JSON Formatter focuses on beautifying and minifying.
Does it validate against a JSON Schema?
Not yet. It checks that the text is valid JSON syntax. Schema validation may be added as a separate tool in future.