diff --git a/shell.nix b/shell.nix
index 5936b21..8efeb05 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,8 +1,9 @@
 { pkgs ? import <nixpkgs> { }, ... }:
 pkgs.mkShell {
-  buildInputs = [
-    pkgs.nixpkgs-fmt
+  buildInputs = with pkgs; [
+    treefmt
+    nixpkgs-fmt
     # To enable webhint to analyze source files
-    pkgs.nodejs
+    nodejs
   ];
 }
diff --git a/treefmt.toml b/treefmt.toml
new file mode 100644
index 0000000..8309d20
--- /dev/null
+++ b/treefmt.toml
@@ -0,0 +1,3 @@
+[formatter.nix]
+command = "nixpkgs-fmt"
+includes = ["*.nix"]