Simplest node.js http server (http://localhost:3000)

index.js

const http = require('http')
const port = 3000

const requestHandler = (request, response) => {
    console.log(request.url)
    response.end("Running")
}

const server = http.createServer(requestHandler)

server.listen(port, (err) => {
    if(err) {
        return console.log("Error", err)
    }
    console.log(`Listening on port ${port}`)
})

To create the simplest Node.js HTTP server, follow these steps:

Open a new file in your code editor of choice and save it with a .js extension, for example, "server.js".
In the server.js file, add the following code:

const http = require('http');

const hostname = 'localhost';
const port = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello, World!');
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});

Save the server.js file and open a terminal or command prompt window in the same directory as the file.
Run the server by typing node server.js in the terminal or command prompt window.
Open a web browser and navigate to http://localhost:3000/ to see the server running.
The code above creates a simple HTTP server that listens on port 3000 of the localhost. When a request is made to the server, it responds with a status code of 200 and a plain text response of "Hello, World!". You can modify the response to suit your needs or serve different types of content, such as HTML, CSS, or JSON.