JSON Schema Validator

JSON Schema Validator checks a JSON document against a JSON Schema and lists every problem — in your browser.

Validating

Paste the document on the left and the schema on the right. The Result updates as you type:

• ✓ Matches the schema when there are no problems.
• Otherwise, one row per problem: the path of the value that failed (like $.address), what is wrong (Missing required property "country".) and the schema keyword that caught it (required).

Click a row to put the cursor on that value in your JSON. Copy report copies every problem as path: message, one per line.

Versions

Auto version reads the schema’s $schema and picks the matching draft, or 2020-12 when there isn’t one. You can choose one yourself:

Choice	Use for
2020-12	New schemas, OpenAPI 3.1
2019-09	Schemas that say draft/2019-09
Draft 7	Most older schemas, including draft 6
Draft 4	OpenAPI 3.0-era and legacy schemas

format is checked, not ignored: date, time, date-time, duration, email, hostname, ipv4, ipv6, uri, uri-reference, uuid, json-pointer, regex and more.

$ref works within the schema (#/$defs/…, #/definitions/…, $anchor). Schemas on other websites are not downloaded.

Generating a schema

No schema yet? Press Generate from JSON. It writes a 2020-12 schema from the document on the left:

• every property with its type, including nested objects and arrays;
• required lists the keys of each object — for arrays of objects, only keys present in every item;
• common string formats are spotted: date-time, date, email, uri.

Treat it as a starting point: add minimum, enum, pattern or additionalProperties: false where your data needs them. If the schema editor already has your own schema, press the button twice to replace it.

Privacy

Validation runs in your browser. Your last document and schema are remembered on this device only; Clear removes them. Share puts both in the link after #, which is never sent to a server.