OpenAPI

A language-agnostic specification for describing REST APIs

OpenAPI allows both computers and humans to understand the capabilities of a REST API without direct access to the source code.

Its main goals are to:

• Minimize the amount of work needed to connect decoupled services.

• Reduce the amount of time needed to accurately document a service.

The two main OpenAPI implementations for .NET are Swashbuckle and NSwag.

Swagger is tooling released by SmartBear that uses the OpenAPI specification. For example, OpenAPIGenerator and SwaggerUI.