diff --git a/flake.nix b/flake.nix
index 398bb91..0d5e752 100644
--- a/flake.nix
+++ b/flake.nix
@@ -29,8 +29,6 @@
       ];
 
       imports = [
-        inputs.treefmt.flakeModule
-
         ./assets
         ./hosts
         ./modules
@@ -39,31 +37,7 @@
 
       flake.devShells = transpose (builtins.mapAttrs (_: shell: shell.result) nilla.shells);
       flake.packages = transpose (builtins.mapAttrs (_: pkg: pkg.result) nilla.packages);
-
-      perSystem = {
-        treefmt = {
-          programs.deadnix.enable = true;
-          programs.nixfmt.enable = true;
-          programs.statix.enable = true;
-          programs.fish_indent.enable = true;
-          programs.deno.enable = true;
-          programs.stylua.enable = true;
-          programs.shfmt.enable = true;
-          settings.global.excludes = [
-            # agenix
-            "*.age"
-
-            # racket
-            "*.rkt"
-            "**/rashrc"
-
-            # custom assets
-            "*.png"
-            "*.svg"
-          ];
-          settings.on-unmatched = "fatal";
-        };
-      };
+      flake.formatter = nilla.packages.formatter.result;
     };
 
   inputs = {
diff --git a/modules/nilla/builders/custom-load.nix b/modules/nilla/builders/custom-load.nix
index b89bc36..b340dec 100644
--- a/modules/nilla/builders/custom-load.nix
+++ b/modules/nilla/builders/custom-load.nix
@@ -1,12 +1,7 @@
 { lib }:
 {
   config.builders.custom-load = {
-    settings.type = lib.types.submodule {
-      options.args = lib.options.create {
-        type = lib.types.null;
-        default.value = null;
-      };
-    };
+    settings.type = lib.types.submodule { };
     settings.default = { };
     build = pkg: lib.attrs.generate pkg.systems (system: pkg.package { inherit system; });
   };
diff --git a/nilla.nix b/nilla.nix
index 70446e8..af9de9a 100644
--- a/nilla.nix
+++ b/nilla.nix
@@ -61,6 +61,16 @@
             ];
           }
         );
+        formatter = {
+          inherit systems;
+          builder = "custom-load";
+          package =
+            { system }:
+            let
+              eval = inputs.treefmt.lib.evalModule inputs.nixpkgs.legacyPackages.${system} ./treefmt.nix;
+            in
+            eval.config.build.wrapper;
+        };
       };
 
     config.shells.default = {
diff --git a/treefmt.nix b/treefmt.nix
new file mode 100644
index 0000000..93590a2
--- /dev/null
+++ b/treefmt.nix
@@ -0,0 +1,23 @@
+{
+  projectRootFile = "nilla.nix";
+  programs.deadnix.enable = true;
+  programs.nixfmt.enable = true;
+  programs.statix.enable = true;
+  programs.fish_indent.enable = true;
+  programs.deno.enable = true;
+  programs.stylua.enable = true;
+  programs.shfmt.enable = true;
+  settings.global.excludes = [
+    # agenix
+    "*.age"
+
+    # racket
+    "*.rkt"
+    "**/rashrc"
+
+    # custom assets
+    "*.png"
+    "*.svg"
+  ];
+  settings.on-unmatched = "fatal";
+}