Business Services
Business services are the innermost layer of the Layered Service Architecture. They are responsible for providing the core business functionality, also known as Domain Logic, of the system. They are the only layer that is allowed to interact directly with the Event Stream.
Business services have no connection to the user interface. They are only accessible through the Backend for Frontend (BFF) services over transports such as HTTP or RPC.
Clients
Business services are accessed through business service clients. Clients are responsible for making requests to the business services and handling the responses. They are the only layer that is allowed to interact directly with the business services.