Architecture Patterns

---
triggers:
  - "architecture patterns"
name: architecture-patterns
description: Implement proven backend architecture patterns including Clean Architecture, Hexagonal Architecture, and Domain-Driven Design. Use when architecting complex backend systems or refactoring existing applications for better maintainability.
---

# Architecture Patterns

Master proven backend architecture patterns including Clean Architecture, Hexagonal Architecture, and Domain-Driven Design to build maintainable, testable, and scalable systems.

## When to Use This Skill

- Designing new backend systems from scratch
- Refactoring monolithic applications for better maintainability
- Establishing architecture standards for your team
- Migrating from tightly coupled to loosely coupled architectures
- Implementing domain-driven design principles
- Creating testable and mockable codebases
- Planning microservices decomposition

## Core Concepts

### 1. Clean Architecture (Uncle Bob)

**Layers (dependency flows inward):**

- **Entities**: Core business models
- **Use Cases**: Application business rules
- **Interface Adapters**: Controllers, presenters, gateways
- **Frameworks & Drivers**: UI, database, external services

**Key Principles:**

- Dependencies point inward
- Inner layers know nothing about outer layers
- Business logic independent of frameworks
- Testable without UI, database, or external services

### 2. Hexagonal Architecture (Ports and Adapters)

**Components:**

- **Domain Core**: Business logic
- **Ports**: Interfaces defining interactions
- **Adapters**: Implementations of ports (database, REST, message queue)

## Note
Skill content truncated for token efficiency. Full version available in the source repository.