Which REST constraint allows intermediaries to provide shared services such as caching without the client needing to know about the final server?

Which REST constraint allows intermediaries to provide shared services such as caching without the client needing to know about the final server?

• A. Code on Demand
• B. Uniform Interface
• C. Layered System
• D. Cacheable

Answer: (C)

Layered System In REST, this constraint allows the architecture to be composed of multiple layers, with each layer only interacting with the one directly alongside it. That means intermediaries like proxies, gateways, or caches can sit between the client and the final server and provide shared services such as caching, authentication, or load balancing. The client talks to the nearest layer and remains unaware of the actual server behind it, so the final destination can change or scale without the client needing to know. This decoupling is what enables intermediaries to offer services without the client needing to know where the response ultimately came from. Code on Demand focuses on sending executable code to extend client functionality, not on intermediary placement. Uniform Interface governs how resources are identified and interacted with, not the presence of intermediary layers. Cacheable deals with marking responses as cacheable to enable caching, but it doesn’t describe the architectural layering that allows intermediaries to provide shared services invisibly to the client.

Layered System

In REST, this constraint allows the architecture to be composed of multiple layers, with each layer only interacting with the one directly alongside it. That means intermediaries like proxies, gateways, or caches can sit between the client and the final server and provide shared services such as caching, authentication, or load balancing. The client talks to the nearest layer and remains unaware of the actual server behind it, so the final destination can change or scale without the client needing to know. This decoupling is what enables intermediaries to offer services without the client needing to know where the response ultimately came from.

Code on Demand focuses on sending executable code to extend client functionality, not on intermediary placement. Uniform Interface governs how resources are identified and interacted with, not the presence of intermediary layers. Cacheable deals with marking responses as cacheable to enable caching, but it doesn’t describe the architectural layering that allows intermediaries to provide shared services invisibly to the client.