nixos-config/modules/system/services/server/transmission/default.nix

{ pkgs, config, ... }:
{
  imports = [
    ./nginx
  ];

  services.transmission = {
    enable = true;
    credentialsFile = config.age.secrets.transmissionPass.path;
    openPeerPorts = true;
    settings = {
      rpc-authentication-required = true;
    };
  };
}