architecture-patterns

Backend architecture relies on clear separation of concerns across layers—domain logic, use cases, adapters, and infrastructure—with dependencies pointing inward. Clean Architecture and Hexagonal patterns achieve this by isolating business rules from frameworks, enabling testability and future-proofing.

Both enforce inward-pointing dependencies and framework independence. Hexagonal (ports and adapters) emphasizes swappable implementations at system boundaries; Clean Architecture adds explicit layer structure. Both solve the same core problem—loose coupling and maintainability—with slightly different terminology.

Start by mapping domain boundaries using Domain-Driven Design concepts: identify entities, aggregates, and repositories within your monolith. Then establish clear adapters (ports) between domains, migrate each bounded context to its own layer or service, and ensure dependencies flow only toward the core domain logic.

Apply DDD when your system has complex business logic, multiple team domains, or long-term maintainability needs. DDD clarifies domain boundaries through aggregates, entities, and repositories—reducing coupling between teams and making architecture changes safer as requirements evolve.

Yes. Clean Architecture, Hexagonal, and DDD are framework-agnostic patterns. They specify layer boundaries and dependency direction, not technology choices. Ports and adapters decouple your domain from frameworks, so you can swap implementations—database, web server, messaging—without rewriting core logic.

Define your domain core first: identify entities, use cases, and aggregates. Then add adapters (ports) for external dependencies—database, API clients, messaging. Finally, layer infrastructure around them. This skeleton enforces dependency direction and testability from the start, avoiding rework.