Test learners' ability to analyze performance and scalability trade-offs of common web-application caching strategies—including client-side, CDN, server-side, in-memory and distributed caches—by evaluating metrics (hit rate, latency percentiles, throughput), consistency and invalidation approaches (TTL, cache coherence, purge), eviction policies, cost and operational complexity, and by recommending appropriate strategies for given workload scenarios and scaling requirements. Scope: medium-complexity analysis, scenario-based decision making, and justification of trade-offs.