What problem does it solve? Designing backend systems without clear architectural boundaries leads to tightly coupled code, untestable business logic, and painful refactoring. This Skill provides proven architecture patterns and implementation guidance to build maintainable, testable, and scalable backend systems. ## Core Features & Use Cases - Clean Architecture Guidance: Layered structure with entities, use cases, adapters, and infrastructure, enforcing the dependency rule so business logic stays framework-independent. - Hexagonal Architecture (Ports & Adapters): Define ports as interfaces and swap adapters (e.g., Stripe vs. mock payment gateways) for testing and flexibility. - Domain-Driven Design: Tactical patterns including entities, value objects, aggregates, repositories, and domain events, plus strategic patterns like bounded contexts. - Use Case: When refactoring a monolithic order-processing application, use this Skill to define module boundaries, extract domain entities with business rules, and create repository interfaces so the core logic can be tested without a database. ## Quick Start Ask the AI to design a Clean Architecture structure for a new backend service, including domain entities, use cases, and repository interfaces.
