JSON Schema Generator — Generate from Sample JSON

The JSON Schema Generator automatically infers a JSON Schema (Draft-7) from any sample JSON object. Instead of writing schemas by hand, simply paste a representative JSON document and get a complete, validated schema in seconds.

What is JSON Schema?

JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes the structure, data types, and constraints of your JSON data. Draft-7 is one of the most widely supported versions and is used by tools like Ajv, Postman, and many API gateways.

How the inference works

null values become {"type": "null"}
Integers (whole numbers) use type: integer
Decimals use type: number
Arrays infer their item schema from the first element
Objects recursively infer all nested properties
All keys can be marked as required automatically

Common use cases

Validating API request/response payloads
Generating TypeScript types from JSON data
Building form validation schemas
Documenting data structures for OpenAPI/Swagger specs

What is JSON Schema?

How the inference works

null values become {"type": "null"}
Integers (whole numbers) use type: integer
Decimals use type: number
Arrays infer their item schema from the first element
Objects recursively infer all nested properties
All keys can be marked as required automatically

Common use cases

Validating API request/response payloads
Generating TypeScript types from JSON data
Building form validation schemas
Documenting data structures for OpenAPI/Swagger specs