C# Academy · Lesson

Generating OpenAPI Documents

Produce machine-readable API specs.

What Is OpenAPI?

OpenAPI is a standard, machine-readable description of an HTTP API. From it you can generate docs, client SDKs and test tooling.

.NET 9 ships built-in OpenAPI document generation, replacing the older Swashbuckle dependency for many apps.

// OpenAPI document = JSON describing paths, schemas, params

The built-in support lives in Microsoft.AspNetCore.OpenApi. In .NET 9 templates it is already referenced.

dotnet add package Microsoft.AspNetCore.OpenApi