Layered (N‑Tier) Architecture

Layered architecture separates concerns into layers such as presentation, application and data. Each layer exposes services to the layer above and hides implementation details below.

When it fits

• Traditional web apps, internal tools and line‑of‑business systems
• Teams using frameworks that naturally promote layers like Rails, Django or Spring

Risks

• Layers can become anaemic pass‑throughs if not designed with strong domain boundaries
• Cross‑cutting concerns duplicated in multiple layers

Real‑world examples

• Content management systems and many enterprise CRUD apps ship successfully with a classic 3‑tier structure
• WordPress deployments and Django admin apps follow layered patterns for speed and simplicity

Practical tips

• Keep domain logic out of controllers and views
• Centralise cross‑cutting concerns in middleware or shared services