What is Node.js

Node.js is an open-source, cross-platform, JavaScript runtime environment that executes JavaScript code outside of a browser.  Node.js is a platform built on Chrome's JavaScript runtime for easily building fast and scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.React is a frontend library, which runs in the browser,Since React and Angular are purely client-side libraries made up of JavaScript files, any old HTTP server can send them to users – PHP inside Apache, Java Tomcat, Rails inside Passenger, and yes, Node.js.
Node.js connects the ease of a scripting language (JavaScript) with the power of Unix network programming. Node.js was built on the Google V8 JavaScript engine since it was open-sourced under the BSD license.
Why would I use node JS?
Node.js is primarily used for non-blocking, event-driven servers, due to its single-threaded nature. It's used for traditional web sites and back-end API services, but was designed with real-time, push-based architectures in mind.
Is Node JS good for backend?
Node.js not only revolutionized backend web development but also contributed to bringing performance to the frontend by bringing serious engineering to the client-side. It's also played a part in the expansion of the overall JavaScript ecosystem and the improvement of modern JS frameworks such as Angular, React or Vue.
Node.js is more extensive and faster compared to PHP which may make it a more viable choice. However, some programmers prefer PHP because it is easier to pick up than a Node.js and features an integrated database. One is not better than the other
Node.js has been a game-changing technology since its initial release back in 2009. Consequently, Node.js represents a “JavaScript everywhere” paradigm, unifying web application development around a single programming language, rather than needing different languages for server-side and client-side scripts.