You have a .example-usercontent.com wildcard certificate for domains like user-1234.example-usercontent.com and you have millions of users. A wildcard certificate is appropriate because:
* LetsEncrypt rate limits are a thing
* The domains exist to leverage origin sandboxing in browsers, but are served by the same infrastructure. It's not more secure (but it is more complicated) to have more certificates here.
Generally, the assumption that two subdomains are served by independent infrastructure is often wrong. Think of things like blogger.com/blogspot.com. So the concern about compromising keys doesn't really apply.
You have a .example-usercontent.com wildcard certificate for domains like user-1234.example-usercontent.com and you have millions of users. A wildcard certificate is appropriate because:
* LetsEncrypt rate limits are a thing
* The domains exist to leverage origin sandboxing in browsers, but are served by the same infrastructure. It's not more secure (but it is more complicated) to have more certificates here.
Generally, the assumption that two subdomains are served by independent infrastructure is often wrong. Think of things like blogger.com/blogspot.com. So the concern about compromising keys doesn't really apply.