When should you not use Node.js?

Short answer: Node.js is awesome for I/O-heavy, real-time apps, but it’s not ideal for: CPU-intensive tasks: Heavy computations block the event loop and slow down all requests.

Explain a bit more

Applications requiring multithreaded parallelism: Though worker threads exist, Node.js is not designed for parallel CPU-heavy workloads by default. When you need mature libraries for complex domains: Some domains (like machine learning) have better ecosystems in other languages.

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.