architecture-patterns

Refactor a monolith by applying Clean Architecture and Domain-Driven Design principles to define bounded contexts, establish inward dependency flow, and separate domain logic from framework concerns. This creates loosely coupled backend modules that are independently testable and easier to maintain.

Make domain logic independently testable by implementing Hexagonal Architecture (Ports and Adapters). Define port interfaces for external interactions and implement adapters to enable swapping implementations and easy testing with mocks, keeping the business core technology-agnostic.

Structure a backend project by organizing entities, use cases, interface adapters, and infrastructure so dependencies flow inward. Define ports for external interactions, implement adapters for swapping implementations, and keep the business core framework-agnostic.

You need Domain-Driven Design for microservice decomposition when modeling complex systems with distinct bounded contexts. It helps model ubiquitous language, use aggregates and repositories, and define backend module boundaries with a domain-first mindset to ensure consistent invariants.

Clean Architecture works with existing backend frameworks by organizing infrastructure as outer layer adapters. It enforces inward dependency direction and port/adapter separation, ensuring your technology-agnostic business core remains independent of specific framework implementations.

Tightly coupled backend systems become expensive to change because domain logic and framework concerns are mixed. Clean Architecture and Hexagonal Ports and Adapters solve this by enforcing clean separation, enabling swapping implementations, and making domain logic independently testable.