diff --git a/flake.lock b/flake.lock
index c9f1b7d4..62b432a8 100644
--- a/flake.lock
+++ b/flake.lock
@@ -239,11 +239,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1745234285,
-        "narHash": "sha256-GfpyMzxwkfgRVN0cTGQSkTC0OHhEkv3Jf6Tcjm//qZ0=",
+        "lastModified": 1745391562,
+        "narHash": "sha256-sPwcCYuiEopaafePqlG826tBhctuJsLx/mhKKM5Fmjo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "c11863f1e964833214b767f4a369c6e6a7aba141",
+        "rev": "8a2f738d9d1f1d986b5a4cd2fd2061a7127237d7",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index b04628cb..28f35d36 100644
--- a/flake.nix
+++ b/flake.nix
@@ -135,13 +135,12 @@
               editorconfig-checker.enable = true;
               hlint.enable = true;
 
-              nixfmt-rfc-style = {
+              treefmt = {
                 enable = true;
-                settings.width = 80;
+                package = self.formatter.${system};
               };
 
               statix.enable = true;
-              stylish-haskell.enable = true;
               typos.enable = true;
               yamllint.enable = true;
             };
@@ -181,7 +180,8 @@
                 check
                 inputs.home-manager.packages.${system}.default
                 self.checks.${system}.git-hooks.enabledPackages
-              ];
+                self.formatter.${system}
+              ] ++ self.formatter.${system}.runtimeInputs;
             };
 
           ghc = pkgs.mkShell {
@@ -190,6 +190,30 @@
           };
         };
 
+        formatter = pkgs.treefmt.withConfig {
+          runtimeInputs = with pkgs; [
+            nixfmt-rfc-style
+            stylish-haskell
+          ];
+
+          settings = {
+            on-unmatched = "info";
+            tree-root-file = "flake.nix";
+
+            formatter = {
+              stylish-haskell = {
+                command = "stylish-haskell";
+                includes = [ "*.hx" ];
+              };
+              nixfmt = {
+                command = "nixfmt";
+                options = [ "--width=80" ];
+                includes = [ "*.nix" ];
+              };
+            };
+          };
+        };
+
         packages =
           let
             universalPackages = {