Explain CORS and how to configure it in Node.js.

Short answer: Cross-Origin Resource Sharing controls which domains can access your API. Configure with the cors package: const cors = require('cors'); app.use(cors({ origin: ' }));

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.