fourlayered

Fourlayered is a term used in systems design and software architecture to describe structures that divide components into four distinct layers. While the exact responsibilities of each layer vary by domain and organization, the four-layer approach centers on separating concerns to improve maintainability, scalability, and resilience.

A common four-layer configuration includes: a presentation layer that handles user interfaces and interaction; an application or service layer that coordinates tasks and business processes; a domain or business logic layer that encapsulates core rules and domain models; and a data, persistence, or infrastructure layer that manages storage, retrieval, external services, and messaging. Some variants swap the data and domain roles or replace the infrastructure layer with an integration layer, depending on architectural priorities.

Benefits of a fourlayered design typically include clearer responsibilities, easier testing, and greater modularity, which can facilitate independent evolution of layers and improve adaptability to changing requirements. Potential drawbacks include added architectural overhead and the need for well-defined interfaces between layers to prevent tight coupling.

In practice, the term fourlayered is not standardized and its exact meaning can differ across organizations and fields. It is often used informally to describe any four-tier separation of concerns within a system. See also multi-tier architecture and layered architecture for related concepts.