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About JSON Schema Validator Online
This tool validates JSON documents against a JSON Schema. Provide the schema and the data, and the tool checks every property against its declared type, format, constraints, and structure — reporting all violations with paths so you can find them in your data.
JSON Schema is the industry standard for describing the structure of JSON data. It's used in OpenAPI specifications, configuration validation, form validation, and API request/response contracts.
The validator supports recent drafts (Draft 7, 2019-09, 2020-12) and handles complex features like $ref references, conditional schemas (if/then/else), and content encoding. Useful for API contract testing, configuration file validation, and ensuring schema compliance before persisting data.
How to use this tool
How to do a basic JSON Schema sanity check against data
Paste the schema
Drop your JSON Schema into the "Schema" field. The tool only looks at `type` ("object" / "array" / "string" / "number" / "boolean" / "null") and `required` (array of property names). Other keywords like `properties`, `enum`, `pattern`, `format`, `minimum`, `items` are NOT enforced.
Paste the JSON data
Drop the candidate document into the "Data" field. Both fields must be valid JSON — syntax errors throw "Invalid Schema JSON." or "Invalid Data JSON." before validation runs.
Press Run
Result returns `valid` (boolean) plus `errors` (array of strings). Errors look like "Type mismatch: expected number" or "Missing required: id". Empty `errors` and `valid: true` mean the smoke test passes.
When you need a real validator
This is a smoke test, not a Draft-2020-12 implementation. For full Schema features ($ref, allOf/anyOf, format checks, conditionals) use a real library like ajv on a server or in Node — the precise feedback there is worth it.