hexagonal-architecture

Hexagonal architecture isolates domain logic by defining explicit inbound and outbound ports that act as boundaries, ensuring infrastructure details remain outside the pure core domain. This enables easy replacement and end-to-end testing.

The best way to structure ports and adapters is by defining a single use-case boundary, implementing explicit port interfaces, and wiring adapters in a central composition root to enable easy replacement and testing.

You test decoupled use cases by applying boundary-driven testing: unit tests for use cases, contract tests for port interfaces, and integration tests for adapters. This ensures domain logic is validated without infrastructure dependencies.

Yes, you can replace an HTTP adapter with a messaging adapter without changing core logic. Explicit port interfaces allow edge adapters for transport and persistence to be swapped in the central composition root without affecting the domain.

You should avoid hexagonal architecture when your application lacks complex domain logic or long-term maintainability requirements. The explicit port interfaces and adapter implementations add structural overhead that may be unnecessary for simple scripts or basic CRUD applications.