clean-ddd-hexagonal
Language-agnostic backend architecture combining DDD, Clean Architecture, and Hexagonal patterns.
- Enforces strict dependency rules (inward only) with clear layer separation: domain (core logic), application (use cases), and infrastructure (adapters)
- Provides tactical DDD patterns including entities, value objects, aggregates, domain events, repositories, and domain services with concrete decision trees for placement
- Includes anti-pattern warnings (anemic models, god aggregates, leaking infrastructure, premature CQRS) and implementation sequencing from domain discovery through adapter implementation
- Covers aggregate boundary design, repository-per-aggregate strategy, eventual consistency via domain events, and transaction management across service boundaries
- Language-agnostic guidance applicable to Go, Rust, Python, TypeScript, Java, and C# with reference documentation on layers, bounded contexts, CQRS, event sourcing, and testing strategies
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.
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