🔷 JSON Schema to TypeScript

What does JSON Schema to TypeScript do?

JSON Schema to TypeScript is a free online tool that automatically converts JSON Schema definitions into TypeScript interfaces and type aliases. Whether you're an API developer, frontend engineer, or full-stack developer, just paste your JSON Schema to get TypeScript-compliant type definitions. The tool uses pure front-end technology — all conversion happens locally in your browser, and no data is ever uploaded to a server.

Core Features

• Auto Type Inference: Automatically generates TypeScript interfaces and type aliases based on JSON Schema type, properties, items, and other fields
• Nested Object Support: Recursively processes nested object and array structures, generating complete type hierarchies
• Enums & Union Types: Automatically identifies enum, oneOf, anyOf, allOf constraints and generates corresponding TypeScript union types and enums
• $ref Resolution: Automatically resolves $ref references, extracting referenced definitions as separate types while maintaining type reference integrity
• Flexible Configuration: Supports export modifiers, JSDoc comments, readonly properties, optional property markers, and other generation options
• Multiple Export Formats: Copy to clipboard with one click or download as a .d.ts type definition file
• History: Automatically saves the last 5 conversion records for easy review and comparison

How to Use

1. Paste or type your JSON Schema definition in the input area, or drag and drop a JSON file.

2. Click a preset button to quickly load a typical JSON Schema example.

3. Adjust generation options as needed: export modifier, JSDoc comments, root interface name, etc.

4. Click "Convert" to generate TypeScript type definitions in real-time.

5. Click "Copy Code" to copy the result to clipboard, or "Download .d.ts" to save as a file.

Use Cases

Use Case 1: API Type Definitions

Backend provides JSON Schema for API request/response formats. Frontend developers use this tool to quickly generate TypeScript type definitions, ensuring type consistency between frontend and backend, reducing communication overhead.

Use Case 2: OpenAPI/Swagger Integration

Extract JSON Schema from OpenAPI specifications and convert to TypeScript types. Use with Axios or Fetch for end-to-end type safety.

Use Case 3: Config File Type Validation

Projects using JSON Schema to validate config file formats can generate corresponding TypeScript types for complete type hints and auto-completion in code.

Use Case 4: Database Model Mapping

Convert database table JSON Schema descriptions to TypeScript interfaces for type-safe data access in the ORM layer.

Use Case 5: Form Validation Type Inference

When using JSON Schema-driven form validation, derive TypeScript types for form data to avoid the repetitive work of writing type definitions by hand.

Extended Knowledge

JSON Schema is a declarative language for describing and validating JSON document structures, with the latest version being Draft 2020-12. It defines keywords like type, properties, items, required, enum, and $ref to constrain JSON data shapes. TypeScript's type system has a natural correspondence with JSON Schema: object maps to interface, array maps to Array<T>, enum maps to union types, and $ref maps to type references. Common conversion challenges include: oneOf/anyOf union type mapping, additionalProperties index signatures, patternProperties dynamic key names, and recursive $ref circular reference detection. Industry-standard conversion libraries like json-schema-to-typescript use pre-compilation for complex scenarios, while this tool uses pure runtime parsing — no dependencies required.