diff --git a/lib/Hikaru/Types.hs b/lib/Hikaru/Types.hs
index 5169d2bf1af817de672dc4407079480c83ea3def..ab025cd9a1ec25a4950998d469f683770df9ed9b 100644
--- a/lib/Hikaru/Types.hs
+++ b/lib/Hikaru/Types.hs
@@ -80,6 +80,9 @@ where
   instance FromParam Double where
     fromParam = readMaybe . unpack
 
+  instance FromParam () where
+    fromParam _ = Just ()
+
   instance FromParam Bool where
     fromParam "true"  = Just True
     fromParam "True"  = Just True
@@ -158,6 +161,9 @@ where
   instance ToParam Double where
     toParam = pack . show
 
+  instance ToParam () where
+    toParam _ = ""
+
   instance ToParam Bool where
     toParam True  = "true"
     toParam False = "false"