🔗 API response cache with Redis and ETags

High-traffic REST APIs often suffer from repetitive expensive computation and database queries for read-heavy resources. Without caching, backend systems waste CPU cycles and network bandwidth serving identical responses to clients, causing higher latency and elevated infrastructure costs.

This script solves the problem by combining Redis server-side caching with HTTP ETags (Entity Tags). Server-side caching in Redis reduces backend execution times to near-zero for warm keys, while HTTP ETags enable conditional GET requests (If-None-Match). When a resource hasn't changed, the server returns a lightweight 304 Not Modified header with no response body, dramatically reducing bandwidth usage and client render latency.