architecture-patterns

SKILL.md

Implement proven backend architecture patterns for maintainable, testable, and scalable systems.

Covers three core patterns: Clean Architecture (layered dependency inward), Hexagonal Architecture (ports and adapters), and Domain-Driven Design (bounded contexts, aggregates, value objects)

Includes complete directory structures, code examples, and implementation patterns for Python backends using FastAPI, asyncpg, and similar frameworks

Demonstrates practical separation of concerns: domain entities, use cases, adapters, repositories, and controllers with clear dependency flows

Provides tactical DDD patterns including value objects, entities, aggregates, domain events, and repositories for modeling complex business logic

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)