What is the difference between stateless and stateful applications?

Short answer: Stateless: Each request is independent; no session stored on server. Stateful: Server keeps session info (like login status). Stateless apps scale easier. Testing & Debugging

Real-world example (ShopNest)

A ShopNest BFF in Node.js aggregates catalog and price APIs for the React storefront.

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.