# Build an HTTP Server

> Learn how to build a basic HTTP server in Node.js using the http module and createServer(), handling the request and response objects to send Hello World.

Author: Flavio Copes | Published: 2018-08-19 | Canonical: https://flaviocopes.com/node-http-server/

Here is the HTTP web server we used as the Node Hello World application in the [Node.js introduction](https://flaviocopes.com/nodejs/)

```js
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\n')
})

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

Let's analyze it briefly. We include the [`http` module](https://nodejs.org/api/http.html).

We use the module to create an HTTP server.

The server is set to listen on the specified hostname, `localhost`, on port `3000`. When the server is ready, the `listen` callback function is called.

The callback function we pass is the one that's going to be executed upon every request that comes in. Whenever a new request is received, the [`request` event](https://nodejs.org/api/http.html#http_event_request) is called, providing two objects: a request (an [`http.IncomingMessage`](https://nodejs.org/api/http.html#http_class_http_incomingmessage) object) and a response (an [`http.ServerResponse`](https://nodejs.org/api/http.html#http_class_http_serverresponse) object).

`request` provides the request details. Through it, we access the request headers and request data.

`response` is used to populate the data we're going to return to the client.

In this case with

```js
res.statusCode = 200
```

we set the statusCode property to 200, to indicate a successful response.

We also set the Content-Type header:

```js
res.setHeader('Content-Type', 'text/plain')
```

and we end close the response, adding the content as an argument to `end()`:

```js
res.end('Hello World\n')
```