Is Express a framework for developing server applications on Node.js?

Yes, Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. It simplifies the process of creating web servers and APIs by offering a straightforward API for routing, request handling, and middleware.

Example of a simple server using Express:

const express = require('express');
const app = express();

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

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});