diff --git a/devshell/default.nix b/devshell/default.nix
index 4d5883c..6d81242 100644
--- a/devshell/default.nix
+++ b/devshell/default.nix
@@ -12,6 +12,8 @@ in
     NIX_USER_CONF_FILES = toString (pkgs.writeText "nix.conf"
       ''
         experimental-features = nix-command flakes ca-derivations
+        substituters = https://nix-cache.nul.ie https://cache.nixos.org
+        trusted-public-keys = ${lib.my.nix.cacheKey}
       '');
 
     INSTALLER_SSH_OPTS = "-i .keys/deploy.key";
diff --git a/home-manager/modules/common.nix b/home-manager/modules/common.nix
index fa393f6..c7ced48 100644
--- a/home-manager/modules/common.nix
+++ b/home-manager/modules/common.nix
@@ -228,6 +228,15 @@ in
             exact = true;
           };
         };
+        settings = {
+          substituters = [
+            "https://nix-cache.nul.ie"
+            "https://cache.nixos.org"
+          ];
+          trusted-public-keys = [
+            lib.my.nix.cacheKey
+          ];
+        };
       };
     })
     (mkIf config.my.isStandalone {
diff --git a/nixos/modules/common.nix b/nixos/modules/common.nix
index affb77b..4f637c0 100644
--- a/nixos/modules/common.nix
+++ b/nixos/modules/common.nix
@@ -48,6 +48,13 @@ in
         settings = {
           trusted-users = [ "@wheel" ];
           experimental-features = [ "nix-command" "flakes" "ca-derivations" ];
+          substituters = [
+            "https://nix-cache.nul.ie"
+            "https://cache.nixos.org"
+          ];
+          trusted-public-keys = [
+            lib.my.nix.cacheKey
+          ];
         };
         registry = {
           pkgs = {