Processed locally — your file never leaves your device
JSON Validator
Check whether JSON is valid, with a clear error message if it isn't — entirely in your browser.
How it works
- Paste JSON, or open a .json file.
- Click Validate.
- A specific parse error is shown if the JSON is invalid; otherwise you'll see a confirmation.
Frequently asked questions
- Is my JSON uploaded anywhere?
- No. Validation happens locally using your browser's own built-in JSON parser.
- What do I get if the JSON is invalid?
- The specific parse error (for example, a trailing comma or an unquoted key), rather than a generic failure message.
- Does this check against a schema?
- No — it checks JSON syntax only, not the shape or types your application expects (that would need a JSON Schema validator).
- Can I open a file instead of pasting?
- Yes, there's an Open file button, or you can paste text directly.