JSON Schema Generator
Infer and generate Draft-07 / 2020-12 JSON Schema definitions from sample JSON documents.
How It Works & Processing Standards
Infer and generate Draft-07 / 2020-12 JSON Schema definitions from sample JSON documents.
Your input data is never sent to any server and is securely processed on your device.
Current Limits
- Desktop max file size: 50MB
- Mobile max file size: 20MB
JSON Schema Generator is a 100% free, browser-based online utility. All calculations and file conversions run locally inside your browser (Local-First) without sending data to remote servers, keeping your documents and inputs strictly private.
How to Use JSON Schema Generator
- 1Paste Sample JSONEnter a valid representative JSON document.
- 2Generate SchemaInfer data types, arrays, nested objects, and required properties.
- 3Copy SchemaCopy the generated JSON Schema for API validation.
Examples
Infer Schema from Object
Input: {"id": 1, "name": "Alice", "active": true}
Result: {
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"id": { "type": "integer" },
"name": { "type": "string" },
"active": { "type": "boolean" }
},
"required": ["id", "name", "active"]
}
Common Use Cases
- Creating API contract schemas for OpenAPI/Swagger documentation
- Validating form inputs and configuration payloads in web applications
- Generating type validation schemas for Fastify, Ajv, or Python jsonschema
Frequently Asked Questions (FAQ)
Are null values and optional properties handled?
Yes, fields containing null can be generated as nullable or union types (e.g. ["string", "null"]).