In the previous section, we created a simple web API and learned that the API is the edge of our application. The edge talks with the outside world and accepts requests via HTTP or other communication protocol. To execute these requests, we need an application service that works as an intermediary between edge components and the domain model. Application service is also responsible for entities persistence.

Going forward, we will learn more about command handling and persistence. Also, we will discuss handling exceptions and checking if incoming requests are valid.