Architecture Patterns

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name: architecture-patterns
description: Implement proven backend architecture patterns including Clean Architecture, Hexagonal Architecture, and Domain-Driven Design. Use this skill when designing clean architecture for a new microservice, when refactoring a monolith to use bounded contexts, when implementing hexagonal or onion architecture patterns, or when debugging dependency cycles between application layers.
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# Architecture Patterns

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

**Given:** a service boundary or module to architect.
**Produces:** layered structure with clear dependency rules, interface definitions, and test boundaries.

## When to Use This Skill

- Designing new backend services or microservices from scratch
- Refactoring monolithic applications where business logic is entangled with ORM models or HTTP concerns
- Establishing bounded contexts before splitting a system into services
- Debugging dependency cycles where infrastructure code bleeds into the domain layer
- Creating testable codebases where use-case tests do not require a running database
- Implementing domain-driven design tactical patterns (aggregates, value objects, domain events)

## Core Concepts

### 1. Clean Architecture (Uncle Bob)
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