What is backpressure in Streams?

Short answer: Backpressure happens when data is produced faster than it can be consumed downstream. In Node.js streams, it's a built-in mechanism to: Pause the readable stream when the writable stream is overwhelmed. Prevent memory overload and crashes. This flow control allows producers and consumers to work in sync.

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.