Ddd Hexagonal Architecture

What it does

This skill enables AI agents to design and implement the Hexagonal Architecture (Ports and Adapters) pattern for backend systems. It structures applications so that business logic remains independent of external frameworks, databases, or user interfaces, facilitating easier testing and maintenance.

When to use it

• Building complex enterprise applications where business rules must remain decoupled from infrastructure changes.
• Creating testable microservices where unit tests should not rely on real database connections or network calls.
• Migrating legacy monolithic codebases into modular, maintainable architectures without rewriting core logic.
• Developing systems that require multiple interchangeable input sources (e.g., REST APIs, GraphQL, CLI) and output destinations.

Key capabilities

• Defines Ports (interfaces) to separate business logic from external concerns.
• Implements Adapters to connect the core domain with specific technologies like databases or web frameworks.
• Enforces a dependency direction where the inner circle (domain) never depends on the outer circle (infrastructure).
• Supports both Inbound Adapters (handling requests) and Outbound Adapters (executing operations).

Example prompts

• "Generate a Python class structure for a user management service using Hexagonal Architecture with a repository port."
• "Create a diagram showing how to integrate an external payment gateway as an adapter in a hexagonal design."
• "Refactor this monolithic function into a domain entity surrounded by ports and adapters for better testability."

Tips & gotchas

• This pattern adds initial complexity; ensure your team understands the separation of concerns before implementing.
• Over-engineering simple scripts with full Hexagonal Architecture can introduce unnecessary overhead; reserve it for scalable, long-term projects.