Cache hit rate is the percentage of requests served from cache instead of being recomputed or fetched from the origin system. In AI and API systems, a high hit rate means repeated prompts, responses, or data fragments can be reused, which lowers latency and reduces compute spend. A low hit rate means more requests miss the cache, forcing the system to do full work each time.
In cyber security, cache hit rate matters because it affects both cost and resilience. Attackers can lower it with cache-busting inputs, unique parameters, or rapidly changing requests, increasing backend load and driving up infrastructure bills. Defenders use caching to absorb repetitive traffic, speed up legitimate access, and spot abnormal patterns when hit rates drop suddenly. Monitoring this metric helps operators detect abuse, tune performance, and control the effective cost of serving high-volume workloads.