ddd-hexagonal-architecture

When to use this skill

Use this skill whenever the user wants to:

• Design applications using the hexagonal (ports and adapters) architecture
• Isolate the domain layer from external systems (databases, APIs, messaging)
• Implement dependency inversion so the domain defines interfaces and adapters implement them
• Draw or implement hexagonal architecture diagrams and layering
• Test the domain in isolation using in-memory or mock adapters

How to use this skill

Workflow

1. Define the domain model with entities, value objects, and domain services
2. Define ports (interfaces) in the domain layer for all external interactions
3. Implement adapters that fulfill those port contracts (inbound: HTTP, messaging; outbound: DB, APIs)
4. Wire dependencies so all arrows point inward toward the domain

1. Port Definition (Domain Layer)