JSON Schema Generator
Free online JSON Schema generator. Generate JSON Schema from JSON data instantly. Supports Draft-07 and 2020-12. Perfect for API validation and OpenAPI specs.
How to Use JSON Schema Generator
Paste JSON Data
Paste any JSON object or array into the input panel. The tool analyzes the structure and generates a JSON Schema that describes the data types, required fields, and constraints.
Review the Schema
The generated JSON Schema appears in the output panel. It includes type definitions, required field lists, and example values. Adjust the draft version (Draft-07 or 2020-12) as needed.
Copy and Use
Copy the schema for API documentation, validation, or OpenAPI specs. Use it to validate incoming JSON, generate TypeScript types, or document your API responses.
Frequently Asked Questions
What is JSON Schema?
JSON Schema is a vocabulary that lets you describe and validate JSON documents. It defines what fields are required, what types they should be, and what constraints apply (min/max values, string patterns, array sizes). JSON Schema is used by OpenAPI, Postman, and most API frameworks for request/response validation.
Can I edit the generated schema?
Yes. The generated schema is a starting point. Copy it and customize: add descriptions for each field, set format constraints (email, uri, date-time), add enum values for fields with limited options, and adjust the draft version for your validator. The generator infers types from your data but doesn't know your business logic — you add that.