diff --git a/default.nix b/default.nix
index c1048df..866a700 100644
--- a/default.nix
+++ b/default.nix
@@ -140,7 +140,9 @@ let
     , src
     , nodePackages ? []
     , routes ? [ "/" ]
-    ,
+    , extraHead ? ""
+    , extraBody ? ""
+    , extraPostBody ? ""
     }:
       let
         nodeSource = symlinkJoin {
@@ -207,9 +209,12 @@ let
               <meta name="msapplication-TileImage" content="/appdata/mstile-144x144.png">
               <meta name="msapplication-config" content="/appdata/browserconfig.xml">
               <meta name="theme-color" content="${themeColor}">
+              ${extraHead}
             </head>
             <body>
+              ${extraBody}
             </body>
+            ${extraPostBody}
           </html>
         '';
       in stdenv.mkDerivation {
