Clean Architecture with .NET

Why Clean Architecture?

Clean architecture aims to keep business rules independent from frameworks and infrastructure details. As a result, the core of the application is not affected when the database, UI, or external services change.

Layers

• Domain: Entities and business rules. No external dependencies.
• Application: Use-cases, CQRS handlers and interfaces.
• Infrastructure: Details like EF Core, messaging, file system.
• API/Presentation: Controllers and entry points.

The dependency arrow always points inward, toward the Domain.

Example

public interface IOrderRepository
{
    Task<Order?> GetByIdAsync(Guid id);
    Task AddAsync(Order order);
}

The Application layer depends on this interface; the concrete EF Core implementation lives in the Infrastructure layer. This makes it easy to mock the repository in unit tests.

Conclusion

While clean architecture may feel like over-abstraction at first, it significantly reduces maintenance cost as projects grow.