layerwhether

Layerwhether is a term used in software architecture to describe a pattern of conditional evaluation across layered systems. It refers to placing boolean checks at the layer that owns a condition and propagating the outcome to dependent layers only as needed. The approach aims to minimize cross-layer coupling and to avoid performing work in layers where the condition is not relevant.

The term is not standardized and has appeared in informal discussions, blogs, and some design guidelines as a conceptual approach rather than a formal pattern. In practice, layerwhether encourages defining clear ownership of predicates and using short-circuiting to halt unnecessary processing early.

How it is implemented can vary, but common elements include tagging conditions with their originating layer, using middleware or interceptors to enforce decisions, and applying the checks in a layered order that respects fault tolerance and data ownership. It is often applied to feature flags, access control, validation, and error handling in multi-layer architectures such as client-server, microservices, or modular monoliths.

Benefits of layerwhether include reduced coupling between layers, improved clarity about responsibility boundaries, and potential performance gains from avoiding needless work. Drawbacks include added complexity, potential debugging difficulty when decisions traverse multiple layers, and the risk of inconsistent predicate semantics across layers if not carefully documented.

See also: guard clause, layer pattern, feature flag, conditional rendering, circuit breaker.