diff --git a/src/Patat/Images/Internal.hs b/src/Patat/Images/Internal.hs
index 6ad8864..939f962 100644
--- a/src/Patat/Images/Internal.hs
+++ b/src/Patat/Images/Internal.hs
@@ -1,4 +1,5 @@
 --------------------------------------------------------------------------------
+{-# LANGUAGE DeriveDataTypeable        #-}
 {-# LANGUAGE ExistentialQuantification #-}
 module Patat.Images.Internal
     ( Config (..)
@@ -11,6 +12,8 @@ module Patat.Images.Internal
 --------------------------------------------------------------------------------
 import           Control.Exception (Exception)
 import qualified Data.Aeson        as A
+import           Data.Data         (Data)
+import           Data.Typeable     (Typeable)
 
 
 --------------------------------------------------------------------------------
@@ -23,7 +26,7 @@ data Backend = forall a. A.FromJSON a => Backend (Config a -> IO Handle)
 
 --------------------------------------------------------------------------------
 data BackendNotSupported = BackendNotSupported String
-    deriving (Show)
+    deriving (Data, Show, Typeable)
 
 
 --------------------------------------------------------------------------------