diff --git a/docs/roundcube.nix b/docs/roundcube.nix
index 52cf5b0..147ebb8 100644
--- a/docs/roundcube.nix
+++ b/docs/roundcube.nix
@@ -18,6 +18,7 @@
     # activate plugins
     plugins = [
       "persistent_login"
+      "managesieve" # built-in
     ];
     dicts = with pkgs.aspellDicts; [
       # https://search.nixos.org/packages?query=aspellDicts
@@ -29,6 +30,10 @@
       $config['smtp_host'] = "ssl://${config.mailserver.fqdn}";
       $config['smtp_user'] = "%u";
       $config['smtp_pass'] = "%p";
+
+      $config['managesieve_host'] = "tls://${config.mailserver.fqdn}";
+      $config['managesieve_port'] = 4190;
+      $config['managesieve_usetls'] = true;
     '';
   };