Before we start with mechanism of using Express as the backend framework, let us first explore why we should consider it using or the reasons of its popularity.

• Express lets you build single page, multi-page, and hybrid web and mobile applications. Other common backend use is to provide an API for a client (whether web or mobile).
• It comes with a default template engine, Jade which helps to facilitate the flow of data into a website structure and does support other template engines.
• It supports MVC (Model-View-Controller), a very common architecture to design web applications.
• It is cross-platform and is not limited to any particular operating system.
• It leverages upon Node.js single threaded and asynchronous model.