We will need to use Caddy with 50,000 different domains, can he handle it?

[Whitestrake (Matthew Fay)]

I don’t know if you’ve looked into it yet, but On-Demand TLS may be useful to you when designing your solution with Caddy. I’ve never had a real need or opportunity, but I’ve always been interested in deploying something like this:

@Whitestrake

If I were going to set up a massively multi-tenanted fully-HTTPS shared hosting service, I would probably put Caddy in front with a really simple file:

:80, 443 {
  tls {
    max_certs [some large number]
  }
  proxy / http://haproxy:80 {
    transparent
  }
}

This would make startup pretty fast. I expect I would set [some large number] to the weekly rate-limit of LetsEncrypt and restart Caddy once a week.