Intro
Express is the defacto, unopinionated, minimalist framework for building Node.JS backends. It’s mainly used to render frontend views using template engines like EJS, Pug, or Handlebars—essentially serving dynamic HTML to the browser from server-side code.
Usage
The main purpose of Express is to build a Node server, i.e. a backend. I don’t like this, unless you’re using TypeScript and proper ESLint rules to enforce those types and conventions, otherwise JS in the BE can spell disaster.
However, my opinions aside, Express allows us to spin Node and set up API endpoints, connect to DBs, run our business logic, Server-Side rendering, embed JS into HTML using EJS, handle routes, and serve files…etc. Because of this, it’s sometimes used
However, it's NOT a frontend framework, and should be coupled with frontend JS for interactivity-heavy applications.