Zaidi ya miundo ya kiwango cha kitu (object-level), miundo ya usanifu inabainisha muundo wa kiwango cha juu cha programu — kama layered, hexagonal (ports and adapters), clean architecture, na event-driven. Wanaoganiza mifumo nzima kwa ajili ya uwezekano wa kuendelea, kupima (testability), na kubadilika (flexibility).
Layered (n-tier) architecture
LAYERED → organize the app into horizontal LAYERS, each with a responsibility:
PRESENTATION (UI) → APPLICATION/business logic → DATA ACCESS → DATABASE
→ each layer depends only on the layer below; clear separation
✓ simple, common, organized ✗ can become rigid; layers can leak; less flexible
