ddd-hexagonal-architecture

Hexagonal architecture isolates core domain logic from external concerns by structuring software around a central domain model, using ports and adapters to ensure the business rules remain independent of infrastructure or UI changes.

To implement ports and adapters for a microservice, you define interfaces (ports) for your core domain and create concrete implementations (adapters) for external integrations, achieving loosely coupled, testable systems through dependency inversion.

Hexagonal architecture and clean architecture both enforce dependency inversion to isolate the domain model, focusing on loosely coupled, testable systems where dependencies point inward toward the core business logic rather than outward to infrastructure.

You should use hexagonal architecture when designing systems that require high maintainability and testability, ensuring your core business logic is adaptable to future changes in infrastructure or UI without requiring core domain modifications.

Dependency inversion in hexagonal architecture works by inverting control so that external adapters depend on inner ports, keeping your central domain model independent of databases, UI, and other external infrastructure concerns.