Validate JSON instances against JSON Schema with precise errors, optional formatting, and one-click starter schema generation—for APIs and data contracts.
Validate JSON against JSON Schema with Ajv, pinpoint field errors and generate a starter schema from sample data. A private browser-based tool for API and data testing.
How to use
What is this for?
Check JSON payloads against a schema—types, required keys, string formats—before shipping APIs or editing configs.
Workflow
- Paste JSON on the left and the schema on the right (try Load sample first).
- Optionally click Format on either side, then Validate JSON.
- Need a draft? Put valid JSON on the left, use Generate schema from JSON, then tighten rules on the right.
Tips
- The schema itself must be valid JSON; Draft-07 style keywords work well here.
- Error paths follow JSON Pointer conventions to help you locate fields quickly.