What Is JSON Schema?
JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It describes the shape of your JSON data — what fields are expected, their types, and which are required. This tool generates a draft-07 schema from your data sample.
JSON Schema is essential for:
- API Validation: Ensuring incoming data matches expected formats.
- Documentation: Auto-generating API documentation with data shapes.
- Type Generation: Creating TypeScript types or OpenAPI specs from schema.
- Form Generation: Building dynamic forms with validation rules.
JSON vs. JSON Schema
| Feature | JSON Data | JSON Schema |
|---|---|---|
| Purpose | Contains actual data values. | Describes the structure of data. |
| Validation | Can be validated against a schema. | Used to validate JSON instances. |
| Types | Implicit (string, number, etc.). | Explicit type declarations. |
| Constraints | No constraint information. | min/max, pattern, required, enum. |
| Primary Use | Data exchange, APIs. | Validation rules, docs. |
How to Generate a JSON Schema Online
- Paste a JSON sample: Enter representative data with all field types.
- Click Generate Schema: The tool analyzes types and creates a schema.
- Review required fields: Top-level keys are marked required.
- Use in your project: Validate against this schema using any JSON Schema validator.
Frequently Asked Questions
What JSON Schema version is generated?
The tool generates draft-07 schemas, which is the most widely supported version across validators and tools.
Can I generate sample data from a schema?
Yes. Use bidirectional mode or the Schema to JSON tool to create sample data.
Is this tool safe?
Yes. Processing is 100% client-side.
Real-World Examples
JSON Schema generation is used when building REST APIs that need request validation, creating OpenAPI documentation with accurate data shapes, generating TypeScript types from API responses, and building form validation rules from data models.
Related Tools
- Schema to JSON — Generate sample data from JSON Schema
- JSON to TypeScript — Generate TypeScript interfaces
- JSON Validator — Validate JSON against format rules