diff --git a/nix-os/desktopManagers/cosmic.nix b/nix-os/desktopManagers/cosmic.nix
index 19232de..a26c073 100644
--- a/nix-os/desktopManagers/cosmic.nix
+++ b/nix-os/desktopManagers/cosmic.nix
@@ -18,6 +18,10 @@ in
   config = {
     services.xserver.desktopManager.cosmic.enable = true;
     nixpkgs.overlays = [ cosmicPkgsOverlay ];
+    nix.settings = {
+      substituters = [ "https://cosmic.cachix.org/" ];
+      trusted-public-keys = [ "cosmic.cachix.org-1:Dya9IyXD4xdBehWjrkPv6rtxpmMdRel02smYzA85dPE=" ];
+    };
   };
   options = {
     cosmic-applets = lib.mkOption {default = pkgs.cosmic-applets;};
diff --git a/nix-os/displayManagers/cosmic-greeter.nix b/nix-os/displayManagers/cosmic-greeter.nix
index 7d5a074..b66341a 100644
--- a/nix-os/displayManagers/cosmic-greeter.nix
+++ b/nix-os/displayManagers/cosmic-greeter.nix
@@ -19,6 +19,10 @@ in
     services.xserver.desktopManager.cosmic.enable = true;
     services.xserver.displayManager.cosmic-greeter.enable = true;
     nixpkgs.overlays = [ cosmicPkgsOverlay ];
+    nix.settings = {
+      substituters = [ "https://cosmic.cachix.org/" ];
+      trusted-public-keys = [ "cosmic.cachix.org-1:Dya9IyXD4xdBehWjrkPv6rtxpmMdRel02smYzA85dPE=" ];
+    };
   };
   options = {
     cosmic-greeter = lib.mkOption {default = pkgs.cosmic-greeter;};