clean-ddd-hexagonal

SKILL.md

Clean Architecture + DDD + Hexagonal

Backend architecture combining DDD tactical patterns, Clean Architecture dependency rules, and Hexagonal ports/adapters for maintainable, testable systems.

This skill is an opinionated synthesis of several related architecture traditions. It is not a single canonical architecture model. Use the original source that matches the design question you are answering: DDD for domain modeling, Hexagonal Architecture for ports/adapters, Clean Architecture for dependency direction, Onion Architecture for domain-centered layering, and CQRS/Event Sourcing only for specific read/write or temporal requirements.

When to Use (and When NOT to)

Use When
Skip When

Complex business domain with many rules
Simple CRUD, few business rules

Long-lived system (years of maintenance)
Prototype, MVP, throwaway code

Team of 5+ developers
Solo developer or small team (1-2)

Multiple entry points (API, CLI, events)
Single entry point, simple API

Need to swap infrastructure (DB, broker)
Fixed infrastructure, unlikely to change

High test coverage required
Quick scripts, internal tools

Start simple. Evolve complexity only when needed. Most systems don't need full CQRS or Event Sourcing.