# Using an SSL certificate in a Node.js app

> Load your SSL certificate, private key and CA file in a Node.js app so it serves pages securely over HTTPS.

Source: https://helpcenter.ruachost.com/developers/guides/using-an-ssl-certificate-in-a-node-js-app/

This guide explains how to use an SSL certificate in a Node.js app to enable secure (HTTPS) connections.

### Prerequisites

To use an SSL certificate in a Node.js app, you need the following files:

- **Certificate file** (`.pem` or `.crt`)
- **Private key file** (`.pem`)
- **Certificate Authority (CA) file** (`.pem` or `.crt`)

Upload these files to the server where your Node.js app is stored if you haven’t done so already.

### Loading the SSL Certificate in a Node.js App

You load SSL certificate files by passing their paths to the `https.createServer()` function. The following example demonstrates a basic HTTPS server running on port `9876`:

```
const fs = require('fs');
const https = require('https');

const port = 9876;

const certFile = fs.readFileSync('/path/to/certificate.pem');
const caFile = fs.readFileSync('/path/to/ca_certificate.pem');
const keyFile = fs.readFileSync('/path/to/privatekey.pem');

let options = {
   cert: certFile,
   ca: caFile,
   key: keyFile
};

const httpsServer = https.createServer(options, (req, res) => {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    const message = 'It works!\n';
    const version = 'NodeJS ' + process.versions.node + '\n';
    res.end([message, version].join('\n'));
});

httpsServer.listen(port);
```

#### Running the App

1. Copy the code above into a file, for example `server.js`.
2. Update the `certFile`, `caFile`, and `keyFile` paths to point to your SSL certificate files.
3. Start the application:

```
node server.js
```

4. Open your browser and visit:

```
https://localhost:9876
```

You should see:

```
It works!
NodeJS <version>
```

**Important:** Make sure to use `https://` in the browser address bar; using `http://` will cause the connection to fail.

### More Information

- [https.createServer() documentation](https://nodejs.org/api/https.html#httpscreateserveroptions-requestlistener)
- [SSL options for https.createServer()](https://nodejs.org/api/tls.html#tlscreatesecurecontextoptions)