Performance tuning: caching (in memory, distributed), response?

Short answer: compression In-memory caching stores data on server memory for fast retrieval. Distributed caching uses external stores (Redis, SQL) for multiple servers. Response compression reduces payload size using gzip, Brotli middleware.

Real-world example (ShopNest)

ShopNest registers AppDbContext as Scoped and IMemoryCache as Singleton. Putting DbContext in a Singleton causes threading bugs.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.