Session Persistence (Sticky Sessions):?

Short answer: In stateful applications, requests from the same user need to go to the same service instance. Handling this with load balancing can be challenging, especially in a stateless microservices setup.

Real-world example (ShopNest)

ShopNest splits Catalog, Cart, Order, and Payment into services so teams can deploy catalog changes without redeploying payments.

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.