Express.js is a very popular open source Node.js library that supports the work of backend developers. It was released in 2010 as free software. It allows to create simple web pages and complex hybrid web applications that can be run in the browser. It is characterized by great lightness and efficiency, requires only knowledge of Java Script and HTML, and serves to organize the project on the server side based on MVC (Model-View-Controller) architecture. It is part of the MEAN Software Stack technology written in Java Script, which includes among others Angular.js, Node.js and MongoDB.
Express.js - a flexible middleware
Express.js is used by developers to streamline their work and extend the functionality of Node.js itself. It simplifies and automates complex operations related to API systems, manages HTTP and HTTPS requests, sessions and routing, as well as error handling. It is widely used because of its high flexibility, minimalism and scalability in project work. Its main purpose is to save time when writing and testing code. Since it only requires knowledge of Java Script, it has a low entry threshold, so beginner programmers polish their skills on it.
Express.js handles thousands of client requests in real time, so it is often used to build live chat rooms. Also, it is characterized by high flexibility, as it allows processing requests in the so-called intermediate layer, meaning any request can be included anywhere in the request chain. It also allows, among other things: managing cookies, logging into the service and working in session mode. It provides templates to quickly build dynamic server-side sites. Express.js supports the debugging process and accurately pinpoints code locations containing errors. It works on all operating systems where Node.js is available. It is used by PayPal, IBM or Fox Sports. This Node.js library allows you to minimize project costs because it is free and extremely efficient. An additional plus is that it has many minor libraries created by the developers' community, which solve almost every problem.