architecture-patterns

Hexagonal architecture, or ports and adapters, isolates domain logic by defining ports for external interactions and adapters for implementations. It enforces inward dependencies, keeping the core domain independent of infrastructure, which improves testability and maintainability.

To resolve dependency cycles between architecture layers, enforce strict inward dependencies by restructuring domain models and use cases. Ensure adapters depend inward toward the domain, preventing outer layers from circular references, and validate the structure using in-memory unit tests.

The best way to organize directories for a hexagonal architecture project is to group code by layers: separate directories for domain models, ports, and adapters. This structure clarifies boundaries and supports maintainable systems in both microservices and monoliths.

Yes, you can apply clean architecture, hexagonal architecture, and DDD to both microservices and monoliths. The patterns provide concrete examples for structuring ports and adapters, ensuring robust architectures regardless of your system's deployment scale.

To test domain logic when using ports and adapters, write in-memory or unit tests that target the core domain without external dependencies. This approach leverages the enforced inward dependencies, allowing you to validate use cases independently of infrastructure adapters.