Caching

Caching places copies of data in faster storage — in-memory stores like Redis or Memcached, browser caches, CDN edge caches, or application-level caches — to reduce database load, lower latency, and improve throughput. Effective caching strategies include cache-aside (load into cache on miss), write-through (update cache on write), and TTL-based expiration. The hard part isn't adding a cache — it's cache invalidation: knowing when cached data is stale and needs refreshing. AI-generated code either ignores caching entirely (every request hits the database) or implements naive caching without invalidation, serving users stale data long after it should have been updated.