multiple ssl certificates on single heroku app?

Question

I have an existing multi-tenant heroku app that uses wildcard subdomains to route requests currently serving the following types of requests below over https/ssl using a wildcard ssl certificate

https://app1.example.com https://app2.example.com

Is it possible to add another seperate single domain ssl certificate to serve requests on a url like:

https://app3.custom-domain.com

Assume all requests are being handled by a single dyno

Answer 1

It's possible and not difficult to do.

Just add the domain to Heroku:

heroku domains:add app3.custom-domain.com

As for the certificate, get a multi domain SAN certificate and include all the domains in the SAN field; your wildcard *.example.com and also the separate domain app3.custom-domain.com.

Please note you will still be charged wildcard rates for the wildcard domain in the SAN field. I know because I've done this.