Before configuring the SSL with node.js, please ensure that you have your 'Private Key', 'Certificate' and 'Intermediate(s)' certificates. You might have received the following certificates from Sectigo.

1) your_domain_name.crt (or) OrderNumber.crt - It is your Server Certificate

2) Intermediate Certificates, it depends upon the type of Certificate you purchase. Mostly, you will get them in the following format.

Ex: 'SectigoRSAXXXXXXXXXSecureServerCA.crt' and 'USERTrustRSAAddTrustCA.crt'

Note: You may have received a .ca-bundle file, which includes those Intermediate Certificates. In this case, please download the appropriate certificate from Downloads.

1. Create an https_server.js file using the following values. you can create file with any name using .js extension.

# vim https_server.js

var https = require('https'); var fs = require('fs');
var https_options =
{
key: fs.readFileSync('/path/to/private.key'),
cert: fs.readFileSync('/path/to/your_domain_name.crt'),
ca: [
fs.readFileSync('path/to/SectigoRSAXXXXXXXXXSecureServerCA.crt'),
fs.readFileSync('path/to/USERTrustRSAAddTrustCA.crt')
]
};

https.createServer(options, function (req, res) {
 res.writeHead(200);
 res.end('Welcome to Node.js HTTPS Servern');
}).listen(8443)

2. Now use the following command to start node.js application created in above step.

# node https_server.js

3. To verify the installation, you can use Qualys SSL Server Test.