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JSON Schema Generator

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About JSON Schema Generator

The JSON Schema Generator automatically produces a JSON Schema (Draft-07) from any JSON example you provide. Paste a JSON object and get a complete schema describing its structure: property types, required fields, nested objects, arrays, and primitive types.

JSON Schema is used to validate API request and response bodies, document data structures, configure form validation, generate TypeScript types, and enforce data contracts between services.

The generated schema marks all keys present in the example as required. Edit the output to mark optional fields and add additional constraints like minimum, maximum, pattern, and enum.

Everything runs in your browser. Your data never leaves your device.

How to Use JSON Schema Generator

  1. Paste a JSON example into the input panel.

  2. A JSON Schema is generated instantly based on the structure and types.

  3. Copy the schema and use it in your application, API validator, or documentation.

Examples

Example — Simple object
Input
{"name":"Alice","age":30,"active":true}
Output
{"$schema":"http://json-schema.org/draft-07/schema#","type":"object","required":["name","age","active"],"properties":{"name":{"type":"string"},"age":{"type":"integer"},"active":{"type":"boolean"}}}

Frequently Asked Questions

What JSON Schema version is generated?

Draft-07, which is the most widely supported version across libraries, tools, and frameworks.

Are all fields marked as required?

Yes — all keys present in the example are added to the required array. Remove any properties that are truly optional from the required list in the generated schema.

Does it detect numeric types correctly?

Yes — integers (whole numbers) generate integer type, decimals generate number type, and strings generate string type. Booleans and null are also detected.

Does it handle nested objects and arrays?

Yes — nested objects generate nested schema definitions with their own properties and required arrays. Arrays generate an items definition based on the first array element.

Can I use the generated schema with Ajv, Joi, or Yup?

The generated schema is standard JSON Schema Draft-07 compatible with Ajv. For Joi and Yup, you would need to manually translate the schema to their specific API.