Node.js is a JavaScript runtime and programming environment, built on Chrome's V8 JavaScript engine and designed to build scalable network programs for data-intensive real-time applications. Node.js makes it possible to write event-driven programming in which the programmer only focuses on the parts of the program that need attention, while offloading other functionality onto a server or another device across a network connection to improve performance. One way it accomplishes this is by using an asynchronous execution model, where runtime waits for events from different sources that tell it whether or not to execute any given part of code