JSON Schema Validator
Paste a schema and JSON to inspect the contract tree, validation errors, and exact JSON Pointers instantly.
JSON Schema Validator
Paste a schema and JSON to inspect the contract tree, validation errors, and exact JSON Pointers instantly.
About JSON Schema validation
Connect the contract to each failing path
The validator compiles the pasted schema with Ajv, renders its properties and constraints as a contract tree, and maps each validation error to an instance JSON Pointer. Selecting an error highlights the matching contract path.
Supported drafts and references
This version supports Draft 2020-12 and Draft-07, common string formats, boolean schemas, and local references beginning with #. Remote and file references are rejected instead of being fetched or silently ignored.
Schema and data stay in your browser
Parsing, schema compilation, format checks, contract-tree generation, and validation all run locally in the browser. The tool does not upload the schema, instance data, or validation output.
FAQ
Common questions and answers about this topic.
How do I validate JSON against a JSON Schema?
Paste the schema in the first editor and the JSON instance in the second. The tool compiles the schema and immediately lists each failing JSON Pointer, keyword, and matching schema path.
Which JSON Schema drafts are supported?
Draft 2020-12 and Draft-07 are supported. A schema without a $schema declaration is treated as Draft 2020-12. Other dialects fail explicitly rather than falling back to a different draft.
What does the JSON Pointer in an error mean?
It identifies the exact location in the JSON instance that failed validation. For required or additional properties, the tool extends Ajv's parent path to point directly at the affected property.
Can the validator resolve $ref references?
Yes, local references such as #/$defs/User and #/definitions/User are resolved within the pasted schema. Remote URLs and file references are not fetched.
Why can valid JSON still fail validation?
JSON syntax only determines whether the text can be parsed. JSON Schema adds contract rules such as required properties, value types, formats, ranges, patterns, and allowed enum values.
Are my schema and JSON data uploaded?
No. Parsing, schema compilation, format checks, contract-tree generation, and validation run in your browser. Remote references are rejected, so the validator does not fetch external schema content either.