diff --git a/lib/flake.nix b/lib/flake.nix
index 4655a5d..d208f47 100644
--- a/lib/flake.nix
+++ b/lib/flake.nix
@@ -11,7 +11,9 @@ let
     convert = attr: value: value self inputs imports;
 
     result = (builtins.mapAttrs convert schema.exports);
-  in result // { lib = lib // (result.lib or {}); };
+  in {
+    formatter = builtins.mapAttrs (_: pkgs: pkgs.nixfmt-tree) inputs.nixpkgs.legacyPackages;
+  } // result // { lib = lib // (result.lib or {}); };
 
   flake =  { imports?{}, exports?{}, base?[] }@schema'old: { ... }@inputs'old: { ... }@imports'old: { ... }@inputs'new: base: let
     schema = {