Node.js has a set of built-in modules which you can use without any further installation. Similarly **HTTP module** contains a set of functions which are required to transfer data over the Hyper Text Transfer Protocol (HTTP).
The HTTP module can create an HTTP server that listens to server ports and gives a response back to the client.
In order to to include a module, use the ```require()``` function with the name of the module.
```javascript
const http = require('http');
```
## Node.js as a Web Server
The ```createServer()``` method is used to create an HTTP server. The first argument of the ```res.writeHead()``` method is the status code, ```200``` means that all is OK, the second argument is an object containing the response headers.