Documenting an API is often regarded as a tedious yet essential task. By using OpenAPI / Swagger, which integrates nicely with ASP.NET Core, you can take on this task. In this course, Documenting an ASP.NET Core API with OpenAPI / Swagger, you will gain the ability to document your API. First, you will learn how to add documentation for your API and add a UI that allows testing the API. Next, you will discover how to use attributes and conventions to improve the generated OpenAPI specification. Finally, you will explore how to deal with authentication, versioning and UI customization. When you are finished with this course, you will have the skills and knowledge of OpenAPI needed to correctly document your ASP.NET Core API.