What is the role of the Domain layer in the architecture based on Clean Architecture principles?

In Clean Architecture, the Domain layer is responsible for the application's business logic and is independent of external details (UI, databases, network services). Its main roles:

• Encapsulation of business rules: This describes entities and business rules that are technology-agnostic.
• Use Cases (Interactors): Define specific actions and operations that can be performed with data, implementing business logic.
• Independence: The Domain layer does not depend on other layers, which facilitates testing and maintenance.

For example, if you have an order application, the Domain layer will describe the logic for creating an order, validating it, and calculating its cost, without being tied to a database or UI.

Thus, the Domain layer serves as the heart of the application, ensuring the purity and stability of business logic.