Multi-domain SSL Certificates

If you have a single app that needs to use SSL for multiple domains, you will need a multi-domain SSL certificate.

Multi-domain SSL certificates cost more than single-domain certificates. These certificates are generally priced based on the number of additional domains.

One option for a reasonably priced multi-domain SSL certificate is the PositiveSSL multi-domain certificate from Namecheap.

You do not need a multi-domain certificate if each of your domains is for a different app. In that case, you need a separate SSL certificate for each domain, not a multi-domain SSL certificate.

You can use ServerPilot's
 AutoSSL to get certficates for an unlimited number of domains on your app. However, if you need to include any subdomains, you will need to get a multi-domain certificate.

Example of When You Need a Multi-domain Certificate: WordPress Multisite

If you are running a WordPress multisite instance and two or more domains that are part of the multisite install need SSL, then you will need a multi-domain SSL certificate.