Repeated identical requests without caching waste resources

Without caching, the app repeats the same operations (database queries, computations, API calls) for identical requests, wasting CPU, I/O, and increasing response times unnecessarily.

Implement a caching server like Varnish or Nginx in front of Express to cache request results. Configure appropriate cache headers and TTLs. For application-level caching, use Redis or similar. Identify frequently accessed, infrequently changing endpoints as caching candidates.