Your First Server

Hello, World!

Create an app, define one route, start listening. Save as server.js and run with node server.js.

import express from 'express';

const app = express();

app.get('/', (req, res) => {
  res.send('Hello, World!');
});

app.listen(3000, () => {
  console.log('Server running on http://localhost:3000');
});

Output:

Server running on http://localhost:3000

app, listen, and the request handler

express() creates the app instance. app.get(path, handler) registers a route. app.listen(port) starts the HTTP server and keeps the process alive.

Quick check: What does `app.listen(3000)` do?

• Starts the server and binds it to port 3000
• Registers a new route
• Parses incoming JSON