Comment by miniyarov

At ZudVPN (https://zudvpn.com) we use Caddy to retrieve certificates for subdomain.zudvpn.com where they are later used for VPN connections instead of web server. This makes us be able to issue personal VPNs secured with SSL/TLS on any major Cloud Providers. I would thank both Caddy and Let's Encrypt that opens endless opportunities around secure connection.