Which REST constraint indicates that responses can be cached to improve API performance?

Which REST constraint indicates that responses can be cached to improve API performance?

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

Answer: (D)

Caching responses is what REST supports to improve API performance. This capability comes from the REST constraint that permits Cacheable responses. When a response is marked as cacheable, clients and intermediaries like proxies can store it and reuse it for subsequent requests, which reduces latency and eases the load on the server. This behavior is controlled through HTTP caching headers such as Cache-Control (for example, max-age), Expires, and ETag/If-None-Match for validation. Dynamic or personalized data should be marked non-cacheable to avoid delivering stale information. The other REST constraints organize how clients interact with resources—stateless means each request carries all needed information, Uniform Interface enforces a consistent method of resource manipulation, and Code on Demand allows servers to send executable code—but none of these specifically address caching. Therefore, the constraint that indicates responses can be cached to improve API performance is Cacheable.

Caching responses is what REST supports to improve API performance. This capability comes from the REST constraint that permits Cacheable responses. When a response is marked as cacheable, clients and intermediaries like proxies can store it and reuse it for subsequent requests, which reduces latency and eases the load on the server. This behavior is controlled through HTTP caching headers such as Cache-Control (for example, max-age), Expires, and ETag/If-None-Match for validation. Dynamic or personalized data should be marked non-cacheable to avoid delivering stale information. The other REST constraints organize how clients interact with resources—stateless means each request carries all needed information, Uniform Interface enforces a consistent method of resource manipulation, and Code on Demand allows servers to send executable code—but none of these specifically address caching. Therefore, the constraint that indicates responses can be cached to improve API performance is Cacheable.