These are the following purposes of Node.js:

Real-time web applications
Network applications
Distributed systems
General purpose applications

The purpose of Node.js is to provide a runtime environment for executing JavaScript code on the server-side. It allows developers to build scalable and efficient network applications, particularly web servers, using JavaScript, which was traditionally limited to client-side scripting within web browsers. Node.js uses an event-driven, non-blocking I/O model, making it lightweight and efficient for handling concurrent connections and I/O-heavy tasks. Additionally, Node.js has a vast ecosystem of libraries and frameworks that simplify the development of various types of applications, ranging from web servers to command-line tools and even desktop applications.