Node.js is actually a runtime environment which is based on Chrome’s V8 JavaScript Engine. It is not a framework or a library. Node.js is a platform built on Chrome’s JavaScript runtime for easily building fast and scalable network applications. Node.js is based on an event-driven architecture where I/O runs asynchronously making it lightweight and efficient. It is being used in developing desktop applications as well with a popular framework called electron as it provides API to access OS-level features such as file system, network, etc.