What is Helmet and how does it help secure an app?

Short answer: Helmet is a middleware that sets HTTP headers to protect against common attacks: Adds Content Security Policy (CSP) Prevents MIME sniffing Protects against clickjacking Enables HSTS (HTTPS enforcement) Usage: const helmet = require('helmet'); app.use(helmet());

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.