JSON Schema Generator

Automatically generate a JSON Schema (Draft-07) from any JSON data — for validation, documentation, and code generation.

About JSON Schema Generation

JSON Schema is a vocabulary that allows you to annotate and validate JSON documents. It is widely used for API documentation (OpenAPI/Swagger), form validation, IDE autocompletion, code generation, and data quality enforcement. A JSON Schema describes the expected structure, types, and constraints of a JSON document.

Writing JSON Schema by hand for complex JSON structures is tedious and error-prone. This tool reverse-engineers a JSON Schema from your existing JSON data automatically. It infers types for all properties, handles nested objects and arrays recursively, and optionally marks all present keys as required properties.

The generated schema follows JSON Schema Draft-07, which is compatible with most validators, code generators (quicktype, json-schema-to-typescript), and API documentation tools including Swagger 2.0 and OpenAPI 3.0.

FAQ

What JSON Schema version is generated?
The tool generates JSON Schema Draft-07, which is the most widely supported version and is compatible with OpenAPI 3.0, AJV, Swagger, and most schema validation libraries.
Can the schema validate other JSON files?
Yes. Copy the generated schema and use it with any JSON Schema validator (AJV, jsonschema for Python, etc.) to validate other JSON documents against the expected structure.
How are arrays handled?
Arrays generate a schema with an "items" property describing the type of items. If the array contains objects, the object schema is inferred from the first item. Mixed-type arrays get an empty items schema.

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