Node.js

Suited For:

• A single-page application that provides a quick response.
• Easy to maintain for a single-page application.

Not Suited for:

• The complex application that produces callback hell.

1. Node.js is useful for building one page, fast, light-weight, scalable applications.
2. It is not suitable for building computationally extensive applications, it may lead to bad performance.

If you need a fast, robust and reliable server side framework that allows you to write JS on the backend and therefore have your project in one language - Node.js is a stand out choice. It can easily handle heavy traffic on very little resources (CPU and memory usage is very efficient). I can't recommend it enough, it is such a pleasure to work with - I feel it gave me back my career. I was so bored with the banality of .NET, I had also come to dislike it's overly convoluted and complicated class structure. Node.js was the fresh start I needed, it can be as simple or as complicated as you like - but even at it's most complicated it can still beat the pants off .NET core any day.

Node.js is well suited when we have to serve data to display on a webpage, which will be loaded once the page is load and doesn't make too many requests, or for a small application with fewer visits as for big projects we couldn't rely on a single environment or language.

The ability to process multiple concurrent requests by Node.js is desired for Internet of Things projects that may have thousends or even more devices connecting at the same time.

Node is very good at microservices. "Do one thing and do it well." It is easily Dockerized and scalable. For many products, Node can be used as a front-end API, as well as a back-end processor.
For extremely CPU-intensive tasks, like advanced machine learning, I'd recommend not to use Node.