π Input OpenAPI/Swagger Spec
βοΈ Generation Options
π¦ TypeScript Type Output
// 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 β 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.
β FAQ
What is OpenAPI/Swagger?
OpenAPI (formerly Swagger) is a standardized specification for REST APIs, defining paths, parameters, request/response bodies in YAML/JSON format.
Are OpenAPI v2 and v3 supported?
Yes. The tool auto-detects the format. Both v2 definitions and v3 components/schemas are handled correctly.
Can the generated TypeScript code be used directly?
Yes. The generated code includes interface, type, and enum definitions that can be directly used in your project.
How are $ref references handled?
Automatically resolved into independent TypeScript interfaces. Circular references are detected and handled with type aliases.
Are enum types supported?
Yes. OpenAPI enum fields generate TypeScript union types or enum definitions based on your output options.
Is my data safe?
Completely safe. This tool runs 100% in the browser. Your OpenAPI spec is processed only in local memory, never uploaded to any server.