ddd-clean-architecture

Domain-driven design with clean architecture organizes your ASP.NET Core Web API into four layers—Domain, Application, Infrastructure, and Presentation—each with clear responsibilities. The Domain layer encapsulates business logic through Entities, Value Objects, and Aggregates; the Application layer orchestrates use cases via Commands and Queries; Infrastructure handles persistence and external services; Presentation exposes Controllers or Minimal APIs. This separation enforces dependency inversion and keeps your codebase maintainable as complexity grows.

Bounded Contexts are distinct areas of your business domain where specific terminology and rules apply consistently. In ASP.NET Core backend development, they help you partition large systems into manageable microservices or modules, each with its own domain model and persistence strategy. Using Bounded Contexts prevents ambiguity, reduces coupling, and ensures your API evolves without cross-domain contamination.

Domain Events represent state changes important to your business and are raised by Aggregates when actions occur. Entities are mutable domain objects with unique identity; Value Objects are immutable and defined by their attributes. Implement them in your Domain layer, keep them persistence-ignorant, and wire events through your Application layer to trigger side effects like notifications or state updates, using patterns like the Repository Pattern for data access.

Yes. Entity Framework Core maps your Domain Aggregates to the database while maintaining persistence ignorance in your Domain layer through Repository and Unit of Work patterns. Place EF Core DbContext and mappings in the Infrastructure layer, expose data access through interfaces defined in the Application layer, and keep your business logic free of EF-specific dependencies. This allows you to swap persistence implementations without affecting domain rules.

Refactor when your codebase shows tangled business logic, difficult-to-test controllers, or inconsistent domain patterns across endpoints. Clean architecture and DDD payoff most when building microservices, managing multiple Bounded Contexts, or maintaining complex feature-driven backends where long-term evolution matters. For simple CRUD APIs with minimal business logic, the overhead may not justify the investment.

Dependency Inversion (inject abstractions, not concrete classes), Single Responsibility (each class has one reason to change), and Open/Closed (extend via interfaces, not modification) are core. Clean architecture enforces these through layering, the Repository Pattern for data abstraction, Specifications for query logic, FluentValidation for cross-cutting concerns, and the ErrorOr result pattern for consistent error handling across your API.