JSON Schema Validator
Validate JSON data against a JSON Schema (draft 2020-12, 2019-09 or 07) with Ajv and format checks. Every error shows the instance path. Runs in your browser.
Runs entirely in your browser. Your data is never uploaded.
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View AllWhat is JSON Schema Validator?
The JSON Schema Validator checks JSON data against a JSON Schema and lists all violations – missing required properties, wrong types, out-of-range numbers, invalid formats, extra properties – each with the JSON Pointer of the offending value. Drafts 2020-12, 2019-09 and 07 are supported.
How to use JSON Schema Validator
- Paste the data into JSON data and the schema into JSON Schema (or click Load sample on each).
- Leave Schema version on auto-detect, or choose a draft.
- Read the result: a success message, or the list of errors with their instance paths.
- Fix the data (or schema) and the result updates automatically.
Example
Data: {"age":-1,"email":"x"}
Schema: {"$schema":"https://json-schema.org/draft/2020-12/schema","type":"object","required":["name"],"properties":{"age":{"type":"integer","minimum":0},"email":{"type":"string","format":"email"}}} Validation errors: 3 (draft 2020-12) (root) Missing required property "name" /age Must be ≥ 0 /email Must be a valid "email"
When to use JSON Schema Validator
Use it to test API payloads, config files or schemas you are writing. Draft-04 and older schemas are not supported (Ajv 8 dropped them). Remote $ref URLs are not downloaded; schemas must be self-contained (local $ref to #/$defs/... works).
How JSON Schema Validator works
Validation uses Ajv 8, a widely used JSON Schema implementation, with allErrors enabled so every violation is reported, and ajv-formats for format keywords such as email, date-time, uri and uuid. The draft is detected from the schema's $schema URL (2020-12, 2019-09, otherwise draft-07) or chosen manually. Strict mode is off, so unknown keywords like example are ignored rather than rejected. Common error types are shown with translated messages; others use Ajv's message.
Common Use Cases
- Checking an API request body against its OpenAPI-derived schema
- Debugging why a config file is rejected
- Developing and testing a new JSON Schema
- Validating test fixtures
Security Note
Everything runs locally in your browser; the code you paste is not uploaded.
FAQs
Which drafts are supported?
2020-12, 2019-09 and draft-07 (draft-06 schemas usually work as draft-07). Draft-04 is not supported.
Are formats like email checked?
Yes, via ajv-formats.
Can it load remote $ref schemas?
No, only references inside the same schema.
Why does it show several errors at once?
All errors are collected so you can fix everything in one pass.