diff --git a/config/.config/nvim/lua/pluginconfig/lspconfig.lua b/config/.config/nvim/lua/pluginconfig/lspconfig.lua
index da446907..85dc39f4 100644
--- a/config/.config/nvim/lua/pluginconfig/lspconfig.lua
+++ b/config/.config/nvim/lua/pluginconfig/lspconfig.lua
@@ -75,10 +75,13 @@ function M.setup_null_ls()
   null_ls.setup({
     sources = {
       -- JavaScript
-      null_ls.builtins.formatting.prettier,
-      -- Ppotocol Buffers
+      null_ls.builtins.formatting.biome,
+      null_ls.builtins.formatting.prettierd,
+      -- Potocol Buffers
       null_ls.builtins.diagnostics.buf,
       null_ls.builtins.formatting.buf,
+      -- Nix
+      null_ls.builtins.formatting.nixfmt,
       -- Dockerfile
       null_ls.builtins.diagnostics.hadolint,
       -- GitHub Actions
@@ -87,6 +90,8 @@ function M.setup_null_ls()
       null_ls.builtins.formatting.shfmt.with({
         extra_args = { "-i", "2" },
       }),
+      -- misc
+      null_ls.builtins.diagnostics.semgrep,
     },
     on_attach = function(client, bufnr)
       if client.supports_method('textDocument/formatting') then
diff --git a/flake.nix b/flake.nix
index 897ea912..c81bf524 100644
--- a/flake.nix
+++ b/flake.nix
@@ -20,30 +20,41 @@
       pkgs = nixpkgs.legacyPackages.${system};
 
       users = [
-        { username = "izumin"; homeDir = "/Users/izumin"; hostname = "fleur.local"; }
-        { username = "masayuki.izumi"; homeDir = "/Users/masayuki.izumi"; hostname = "CM2NX3M6CH"; }
+        {
+          username = "izumin";
+          homeDir = "/Users/izumin";
+          hostname = "fleur.local";
+        }
+        {
+          username = "masayuki.izumi";
+          homeDir = "/Users/masayuki.izumi";
+          hostname = "CM2NX3M6CH";
+        }
       ];
 
-      genHomeConfigurations = usersList: builtins.foldl' (acc: user:
-        acc // {
-          "${user.username}" = home-manager.lib.homeManagerConfiguration {
-            inherit pkgs;
-            modules = [
-              { home.username = user.username; home.homeDirectory = user.homeDir; }
-              ./home.nix
-            ];
-          };
-        }
-      ) { } usersList;
+      genHomeConfigurations = usersList:
+        builtins.foldl' (acc: user:
+          acc // {
+            "${user.username}" = home-manager.lib.homeManagerConfiguration {
+              inherit pkgs;
+              modules = [
+                {
+                  home.username = user.username;
+                  home.homeDirectory = user.homeDir;
+                }
+                ./home.nix
+              ];
+            };
+          }) { } usersList;
 
-      genDarwinConfigurations = usersList: builtins.foldl' (acc: user:
-        acc // {
-          "${user.hostname}" = nix-darwin.lib.darwinSystem {
-            inherit pkgs;
-            modules = [ ./darwin-configuration.nix ];
-          };
-        }
-      ) { } usersList;
+      genDarwinConfigurations = usersList:
+        builtins.foldl' (acc: user:
+          acc // {
+            "${user.hostname}" = nix-darwin.lib.darwinSystem {
+              inherit pkgs;
+              modules = [ ./darwin-configuration.nix ];
+            };
+          }) { } usersList;
     in {
       homeConfigurations = genHomeConfigurations users;
       darwinConfigurations = genDarwinConfigurations users;
diff --git a/home.nix b/home.nix
index 716890e6..13c4ddd3 100644
--- a/home.nix
+++ b/home.nix
@@ -1,13 +1,10 @@
 { config, lib, pkgs, ... }:
 
 {
-  nixpkgs.overlays = [
-    (import ./overlays/sheldon.nix)
-  ];
+  nixpkgs.overlays = [ (import ./overlays/sheldon.nix) ];
 
-  nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [
-    "ngrok"
-  ];
+  nixpkgs.config.allowUnfreePredicate = pkg:
+    builtins.elem (lib.getName pkg) [ "ngrok" ];
   # Home Manager needs a bit of information about you and the paths it should
   # manage.
   # home.username = user.name;
@@ -59,6 +56,9 @@
     pkgs.tmux
     pkgs.reattach-to-user-namespace # only darwin
 
+    # nix
+    pkgs.nixfmt
+
     # middlewares
     pkgs.postgresql_16
     pkgs.mysql80