diff --git a/checks/is-formatted.nix b/checks/is-formatted.nix
new file mode 100644
index 0000000..43d4e38
--- /dev/null
+++ b/checks/is-formatted.nix
@@ -0,0 +1,5 @@
+{pkgs ? import <nixpkgs> {}}:
+pkgs.runCommand "check-format" {} ''
+  ${pkgs.alejandra}/bin/alejandra -c ${./.}
+  touch $out
+''
diff --git a/flake.nix b/flake.nix
index 7b2c8ed..2120b4d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -46,7 +46,7 @@
               name
               (value
                 // {
-                  imports = (value.imports or [] ++ [./format-module.nix]);
+                  imports = value.imports or [] ++ [./format-module.nix];
                 })
           )
           customFormats;
@@ -109,8 +109,13 @@
         });
 
         checks = forAllSystems (system: {
-          inherit (self.packages.${system})
-            nixos-generate;
+          inherit
+            (self.packages.${system})
+            nixos-generate
+            ;
+          is-formatted = import ./checks/is-formatted.nix {
+            pkgs = nixpkgs.legacyPackages.${system};
+          };
         });
 
         devShells = forAllSystems (system: let
@@ -136,7 +141,6 @@
           default = nixos-generate;
         });
 
-
         # legacy flake schema compat
         defaultApp = forAllSystems (system: self.apps."${system}".nixos-generate);
         defaultPackage =