Swagger

Swagger is the definitive open-source toolset for designing, documenting, and consuming REST APIs (OpenAPI Specification).

Swagger is a robust collection of open-source tools centered on the OpenAPI Specification (OAS), formerly the Swagger Specification. It streamlines the API lifecycle: use the Swagger Editor to define your API in YAML or JSON; leverage Swagger UI to generate interactive, web-based documentation for testing endpoints; and utilize Swagger Codegen to automatically generate client libraries and server stubs in various languages (e.g., Java, Python). This toolchain ensures precision, accelerates development, and drastically improves API discoverability for both internal teams and external consumers.

https://swagger.io