api-documenter

Define your API's paths, operations, request/response schemas, and security schemes in OpenAPI 3.1 format, including working examples for each endpoint. Validate the spec against your implementation and add authentication flows such as OAuth 2.0 or API keys with concrete samples.

Use code generation tools that consume a valid OpenAPI spec to produce client libraries in languages like Python, JavaScript, and Go. Configure custom templates, manage versions, and integrate generation into CI/CD pipelines for automated releases.

OpenAPI documents synchronous request-response REST APIs, while AsyncAPI covers event-driven and real-time APIs such as message queues and WebSockets. Choose AsyncAPI when your API publishes or subscribes to events rather than serving HTTP requests.

Swagger UI and Redoc both render OpenAPI 3.1 documents, though some advanced 3.1 features like full JSON Schema 2020-12 support vary by tool version. Stoplight Studio is an alternative for collaborative design and documentation of 3.1 specs.

Publish migration guides explaining differences between versions, add deprecation notices with timelines, and maintain version-specific documentation. Automate changelog generation from commits and release notes to keep consumers informed of breaking changes.

Skip full specification workflows for quick internal notes, informal summaries, or pure backend implementation tasks with no exposed API surface. The overhead of OpenAPI authoring only pays off when an API has consumers who need accurate reference docs.