Understanding Layered Architecture
Layered Architecture divides a system into logical layers such as presentation, business, and data access. Each layer has a clear responsibility and interacts only with adjacent layers.
“Layered architecture simplifies governance and onboarding but requires discipline to prevent cross-layer coupling.”
— Viswa
— Viswa
Key Principles
- Separation of concerns between layers.
- Layered dependencies: higher layers use lower layers only.
- Independent testing per layer for maintainability.
Pros & Cons
- Pros: Simple, predictable, easy to onboard new developers, good governance.
- Cons: Cross-layer coupling can occur as teams grow, rigid structure, harder to scale with independent services.
Real-World Examples
- Banking applications with distinct presentation, business, and data layers.
- Traditional enterprise ERP systems.
- Web apps with MVC frameworks like Spring or ASP.NET.
Common Failure Modes
- Direct access to the database from the presentation layer.
- Bypassing business logic for “faster” changes, causing hidden dependencies.
- Adding cross-cutting concerns (like logging, security) improperly across layers.
When to Use
- Teams are small to medium size.
- Governance and predictability are more important than speed.
- System complexity is moderate and scaling is predictable.