JSON Schema Validator
Put a JSON Schema on the left and your data on the right. Every violation is listed with the path in the data and the rule it broke. No schema yet? Draft one from your sample.
How it works
Validation uses Ajv, the most widely used JavaScript JSON Schema validator, with all errors reported rather than stopping at the first one. Formats such as email, date-time, uri and uuid are checked.
The draft is taken from the schema’s $schema keyword when present; otherwise the one you select is used.
An AI-drafted schema is a starting point: it guesses required fields and formats from one example. Review it before relying on it.
Everything above runs in JavaScript inside this tab. Your data is not uploaded. Inputs are remembered in this browser only so they survive a reload; you can switch that off on the privacy page.
Questions
Which JSON Schema version should I use?
Draft 2020-12 is the current release and what OpenAPI 3.1 uses. Draft-07 is still the most widely supported by older tools. Declare it with $schema.
What does "must NOT have additional properties" mean?
The schema sets additionalProperties: false and the data contains a key that is not listed in properties.
Are remote $ref URLs fetched?
No. Only references inside the schema you paste are resolved, so nothing is fetched from the network.