Express.js is a web application framework for Node.js. It is designed to make developing web applications easier and faster. It provides a set of features and tools that allow developers to quickly create robust and efficient web applications.
For example, Express.js makes it easy to create routes for your application. You can define routes with a simple syntax and Express.js will take care of the rest. It also provides middleware for authentication, templating, and serving static files. With Express.js, you can create a fully functional web application in a fraction of the time it would take to do it manually.