Express.js is a minimal and flexible web application framework for Node.js. It is often used as the back-end for web applications, providing a set of features for handling things like routing, middleware, and APIs. With Express, you have full control over the application structure and can choose your own middleware and libraries to use.
Express.js can be used to build the server-side of the application and Next.js can be used to build the front-end, which makes the development process faster and more efficient. This way it’s possible to use the strengths of both technologies in the same project.
Both Express and Next are widely adopted and have big communities, it really depends on the particular needs of your application and your preferences, you can use the one that best fits for your project.