Express
ExplainedFramework
Also known as: Express.js
Minimalist Node.js web framework for building APIs and web servers.
Express, explained
Written by EduVerseWhat it is
Express is a small web framework for Node.js. It gives you a way to define routes, like what should happen on GET /orders or POST /login, and a chain of middleware functions that every request passes through, for jobs like parsing JSON, logging or checking authentication.
Why teams use it
Node.js on its own can serve HTTP, but you’d write a lot of plumbing yourself. Express adds just enough structure without dictating how you organize the rest, which made it the starting point for countless Node.js APIs and tutorials. If you want more structure, NestJS offers it; Fastify focuses on speed.
An example from work
Your team’s backend starts in a file called server.js, with route handlers registered through app.get and app.post, and app.listen at the bottom. You add a POST route, test it with curl, and find req.body is undefined because the JSON middleware, app.use(express.json()), was never added.
Our own explanation, not a quote from the book.
Where it fits
REST APIs and web servers in the Node.js ecosystem
Coverage in the book
Explained and compared with alternatives, so you know where and why it’s used.
