nixos/hosts/sigma/acme.nix

{lib, ...}: {
  security.acme.certs."caspervk.net" = {
    domain = "*.caspervk.net";
    reloadServices = [
      "caddy.service"
    ];
    # The NixOS Caddy module is a little too clever and sets the cert's group
    # to 'caddy', which means other services can't load it. This is not needed
    # since we handle the group membership manually.
    group = lib.mkForce "acme";
  };
  users.groups.acme.members = [
    "caddy"
  ];
}