🔄 OpenAPI to TypeScript Type Generator

// Paste OpenAPI/Swagger spec to auto-generate TypeScript type definitions

What Can OpenAPI to TypeScript Do?

The OpenAPI to TypeScript Type Generator is an online tool for full-stack developers that automatically converts OpenAPI/Swagger specifications into TypeScript interfaces and type definitions. Skip the manual work of writing API types — generate type-safe code with one click, and use with fetch/axios for end-to-end type-safe API calls.

Core Features

• Dual Version Support: Auto-detects Swagger v2 and OpenAPI v3 formats with appropriate parsing logic
• $ref Resolution: Automatically expands $ref references into independent TypeScript interfaces, handling circular references
• Enum Types: OpenAPI enum fields auto-generate TypeScript union types or enum definitions
• Optional Field Handling: Flexible control over optional field marking (? mark or | undefined)
• Description Comments: Preserves OpenAPI description fields as JSDoc comments

How to Use

1. Paste your OpenAPI JSON/YAML spec into the input box, or click "Load Example" for a demo; 2. Select enum output style and optional field marking; 3. The tool auto-generates TypeScript type definitions in real-time; 4. Click "Copy Code" to copy type definitions to clipboard, or download as .d.ts file; 5. Import type definitions in your TypeScript project for type-safe API calls.

Use Cases

Frontend-Backend Collaboration

Backend provides OpenAPI spec, frontend uses this tool to quickly generate TypeScript types for type-safe request parameters and response data.

API Client Generation

Generate complete TypeScript type definitions from OpenAPI specs, combined with code generation tools to build type-safe API client SDKs.

Documentation-Driven Development

In API-first workflows, define OpenAPI specs first, then generate types to ensure code and documentation stay in sync.

Extended Knowledge

OpenAPI (formerly Swagger) is the standardized specification for REST APIs, currently at v3.1. It defines API paths, operations, parameters, request/response bodies in YAML/JSON format. TypeScript type definitions (.d.ts) provide compile-time type checking for API calls, preventing runtime errors. Other popular OpenAPI-to-TypeScript tools include openapi-typescript CLI and openapi-typescript-codegen. This tool provides a convenient online instant-conversion solution.