Architecture Patterns and Methodologies

C4 Model -- Hierarchical Architecture Visualization

Four levels for different audiences:

1. System Context: system + users + external systems (stakeholder view)
2. Containers: applications, data stores, deployment units (technical overview)
3. Components: internal modules within containers (developer view)
4. Code: class/module level (optional, often auto-generated)

Notation/tooling independent. Reduces communication overhead, shared visual language across stakeholders.

Hexagonal Architecture (Ports and Adapters)

Isolate business logic from infrastructure through ports (interfaces) and adapters (implementations).