JSON Schema Validator
This online tool validates JSON data against a JSON Schema. Paste the data and the schema and validation runs locally in your browser (draft-07), reporting each violated constraint, the JSON Pointer path in the data and the line and column of the error so you can locate problems quickly.
How to use it
- 1
Paste the data to validate
Put the JSON you want to check in the left input, or click "Fill example".
- 2
Paste the JSON Schema
Put the constraint schema on the right (draft-07 supported); the example schema is a good starting point.
- 3
Pause to validate
About 400 ms after you stop typing, validation completes in the Worker; compliant data shows as passed, otherwise errors are listed one by one.
- 4
Debug by path
Use the data path and line/column hint in each error to fix the data, and copy the error list in one click when needed.
Key features
Structured error location
Each error carries the data-side JSON Pointer (such as /address/zip), the schema-side path and the triggering keyword, mapped to a data line and column where possible.
Readable error messages
Raw validator messages (type, required, format and so on) are paired with plain-language explanations while keeping the keyword for reference.
draft-07 plus format
Supports the common draft-07 keywords and can enable format checks for email, date-time, uri, uuid and more.
All errors or first error
Switch between returning all errors (the default, up to 200 shown) or just the first, for more controllable debugging of long documents.
Purely local validation
Validation runs entirely in a browser Web Worker, so neither the data nor the schema leaves your device.
One-click copy of errors
Copy the whole error list to paste into an issue or a fix checklist.
Common errors & troubleshooting
- ! The schema $schema declaration states the version; this tool follows draft-07 semantics and treats other common keywords as synonyms.
- ! Errors such as a missing required field or a type mismatch point to the nearest parent data node, and the line and column is a best-effort mapping that may land on the parent.
- ! Turning off "Enable format validation" stops checking semantic formats such as email and date-time, leaving only type checks.
- ! Fix the first reported error first, since later errors can cascade from an earlier structural problem.
Frequently asked questions
Is the validated data uploaded to a server?
No. Parsing and validation happen in a browser Web Worker; this tool has no backend service and the data never leaves your device.
Which JSON Schema versions are supported?
Mainly draft-07, with compatible common keywords that share the same meaning; newer keywords such as prefixItems and unevaluatedProperties are not specially handled.
Why does an error point to a parent node instead of a specific field?
Keywords such as required describe the property set of a parent object, so "missing a field" is inherently a parent-node issue; the specific missing field is named in the error message.
Is the tool free, and do I need to log in?
It is free, with no registration and no usage limits.
Related tools
JSON to JSON Schema
Infer a JSON Schema from a sample JSON document, merging similar fields and marking required properties.
JSON Schema to JSON
Generate example data from a JSON Schema. Supports const / enum / default / examples, local $ref (definitions / $defs), allOf / oneOf / anyOf and semantic format placeholders such as email, date-time and UUID.
JSON Validator
Check whether your JSON is valid. Syntax errors are highlighted with the exact line and column, plus a hint about the token that was expected.
JSON Formatter
Format, beautify and validate JSON in your browser. Errors point to the exact line and column, and you can indent with 2 spaces, 4 spaces or a tab.