arcanea-architecture-patterns

Architecture patterns like layered, hexagonal, microservices, and modular monolith each suit different contexts. Layered architecture works for traditional business apps; hexagonal separates domain logic from adapters; microservices scale independent services; modular monolith balances structure without distribution complexity. Evaluate your team's familiarity, system scale, and maintenance needs to select the best fit.

Monolithic architecture deploys all components as a single unit, simpler initially but harder to scale independently. Microservices split functionality into separate, deployable services that scale and evolve independently but require distributed system management. Modular monolith offers a middle ground: single deployment with internal modularity.

Event-driven architecture decouples services through asynchronous events, ideal for systems needing real-time reactions and loose coupling. CQRS separates read and write models for complex domains with distinct query and command patterns. Event sourcing stores all state changes as immutable events, enabling audit trails and temporal queries.

Architecture patterns involve trade-offs: layered offers simplicity but tight coupling; microservices enable independent scaling but add operational complexity; hexagonal improves testability through clear boundaries; CQRS optimizes read/write performance but requires eventual consistency. Document your system's constraints—team size, scale, deployment frequency, maintenance burden—to weigh each pattern's benefits against your specific needs.

Hexagonal architecture (ports and adapters) separates core domain from external dependencies through well-defined interfaces. You can incrementally refactor existing systems by identifying the domain core, defining ports for external interactions, and extracting adapters for databases, APIs, and frameworks. This improves testability and reduces coupling without requiring a complete rewrite.

Layered architecture organizes code into horizontal layers (presentation, business, data); dependencies flow downward. Clean architecture uses concentric layers with dependency inversion—domain logic at the center, with all dependencies pointing inward. Clean architecture prioritizes business rules independence; layered prioritizes simplicity. Choose clean for complex domains requiring testability; choose layered for straightforward CRUD systems.