diff --git a/modules/cli/git.nix b/modules/cli/git.nix
index 8c2bf2b..3f0a418 100644
--- a/modules/cli/git.nix
+++ b/modules/cli/git.nix
@@ -10,15 +10,18 @@ in {
     options.myOptions.programs.git = {
         enable = mkEnableOption "git";
         userName = mkOption {
-            type = types.str;
+            type = with types; nullOr str;
+            default = null;
             description = "git username";
         };
         userEmail = mkOption {
-            type = types.str;
+            type = with types; nullOr str;
+            default = null;
             description = "git email";
         };
         signingKey = mkOption {
-            type = types.str;
+            type = with types; nullOr str;
+            default = null;
             description = "git commit signing key";
         };
         editor = mkOption {
@@ -46,10 +49,10 @@ in {
                     push.autoSetupRemote = true;
                     commit = {
                         verbose = true;
-                        gpgsign = true;
+                        gpgsign = cfg.signingKey != null;
                     };
                     gpg.format = "ssh";
-                    user.signingkey = "key::${cfg.signingKey}";
+                    user.signingkey = mkIf (cfg.signingKey != null) "key::${cfg.signingKey}";
                     merge.conflictstyle = "zdiff3";
                     interactive.diffFilter = "${pkgs.delta}/bin/delta --color-only";
                     diff.algorithm = "histogram";