Express.js Introduction
📌 Covered in this chapter:
Why Express? · Installing Express · app.listen() · Basic Routes · res.send() / res.json()
Meet Express.js, the most widely used Node.js web framework, and build your very first Express server in a few lines.
1Express.js Introduction — What You'll Learn
Meet Express.js, the most widely used Node.js web framework, and build your very first Express server in a few lines.
Here's everything this chapter covers, in the order you'll learn it:
- What Express.js is
- Why Express is used over raw http
- Installing Express
- Creating an Express server
- app.listen()
- Defining routes
- The request object in Express
- The response object in Express
- res.send()
- res.json()
- Setting status codes
- Organizing routes
2Working Example
💻 Example: Express.js Introduction
JavaScript
▶ Run in Compiler
import express from "express";
const app = express();
app.get("/", (request, response) => {
response.send("Welcome to the Node.js Master Course API");
});
app.listen(3000, () => {
console.log("Server running on port 3000");
});3Best Practices & Common Pitfalls
💡 Key things to remember:
- Express is a thin, unopinionated layer on top of Node's http module — it doesn't replace Node.js, it makes it far more convenient to use.
- Node core concepts (Phases 1–6) matter even when using Express, since Express is built directly on top of them.
❓ Frequently Asked Questions (FAQ)
Q What's the most important thing to understand about express.js introduction?
Focus on: Why Express? · Installing Express · app.listen() · Basic Routes · res.send() / res.json(). These are the core building blocks this chapter's examples are built around, and they show up repeatedly in later chapters of this course.
Q Do I need external npm packages for express.js introduction?
Only where explicitly shown in the code examples above (like Express, Zod, or Socket.IO) — otherwise, this chapter relies entirely on Node.js's own built-in capabilities.