I've never hit te rate limit on LE. Seems to me you need to be running a public site that gives each user a subdomain, or similar setup, before you run into suc

I've never hit te rate limit on LE. Seems to me you need to be running a public site that gives each user a subdomain, or similar setup, before you run into such issues. You don't need a HTTP server to do authentication, it's also possible to use DNS and TLS SNI. There's certainly no need to spawn a server per domain, even for HTTP. If your implementation is complex enough to require many certs, these problems are already solvable. Either fork over the money for a wildcard cert, or account for the extra work in your planning. The setup we use is to have our own authoritative nameserver for a 'dyn' subdomain, and do DNS auth. We auth a subdomain with LE in less than 10 seconds.