Express ( Express.js) is a framework used to build APIs with Node.js. It is an Open source software . It is also useful for building Web-Application. It is relatively minimal with many features available as plugins. Express is also the back-end component of popular development stacks like the MEAN , MERN or MEVN stack, together with the M ongoDB database and a JavaScript front-end framework or library Some useful features of EXPRESS helps in API building routing Concentrate on high-performance HTTP helpers (redirection, caching, etc..). Asynchronous programming It can be installed with the Node Package Manager (NPM). npm i -g express