hexagonal-architecture

Hexagonal architecture (Ports & Adapters) isolates core domain logic from infrastructure concerns by defining explicit domain models, use cases, and inbound/outbound ports, ensuring business logic remains independent from frameworks and persistence details.

Structure ports and adapters by sketching domain boundaries first, then mapping inbound and outbound ports to decouple the core, implementing features with adapters for HTTP, CLI, or DB transport layers within a modular layout.

Use hexagonal architecture when long-term maintainability and testability are priorities, requiring business logic to stay decoupled from transport, frameworks, and persistence layers through explicit domain boundaries.

Yes, the approach provides migration playbooks and guidance for incremental refactors, allowing existing applications to transition toward a domain-focused architecture with a composition root without requiring a full rewrite.

Hexagonal architecture improves testing by decoupling the core domain from adapters, enabling structured testing of use cases and domain models in isolation without relying on infrastructure components like databases or HTTP endpoints.

Applying ports and adapters introduces structural overhead through explicit ports and adapter layers, which may be excessive for simple CRUD applications where domain logic complexity does not warrant full architectural isolation.