What Is OpenAPI?
OpenAPI (formerly Swagger) is the industry standard for describing REST APIs. An OpenAPI specification defines endpoints, request/response formats, authentication, and more in a machine-readable JSON or YAML document. It powers documentation generators, client SDKs, and testing tools.
How to Use This Tool
Define your endpoints as a JSON array with path, method, and description for each. Add a title, version, and base URL. The generator produces a complete OpenAPI 3.0 spec you can use with Swagger UI, Redoc, or any OpenAPI-compatible tool.
API Access
Use our REST API: POST /api/openapi/generate with JSON body containing endpoints, title, version, and base_url. Returns a complete OpenAPI 3.0 specification. Free for 100 calls/day.