diff --git a/Network/Wai.hs b/Network/Wai.hs
--- a/Network/Wai.hs
+++ b/Network/Wai.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE Rank2Types #-}
 {-# LANGUAGE ExistentialQuantification #-}
+{-# LANGUAGE DeriveDataTypeable #-}
 {-|
 
 This module defines a generic web application interface. It is a common
@@ -74,6 +75,7 @@
 import qualified Data.ByteString.Lazy as L
 import Data.Char (toLower)
 import Data.String (IsString (..))
+import Data.Typeable (Typeable)
 
 -- | HTTP request method. Since the HTTP protocol allows arbitrary request
 -- methods, we leave this open as a 'B.ByteString'. Please note the request
@@ -257,6 +259,7 @@
   -- | The client\'s host information.
   ,  remoteHost     :: B.ByteString
   }
+  deriving Typeable
 
 -- | The response body returned to the server from the application. We provide
 -- three separate constructors as optimizations:
@@ -274,6 +277,7 @@
 data ResponseBody = ResponseFile FilePath
                   | ResponseEnumerator Enumerator
                   | ResponseLBS L.ByteString
+  deriving Typeable
 
 data Response = Response
   { status          :: Status
@@ -284,6 +288,7 @@
   -- whatever means it wishes. If 'Right', it will call the 'Enumerator'.
   , responseBody    :: ResponseBody
   }
+  deriving Typeable
 
 type Application = Request -> IO Response
 
diff --git a/wai.cabal b/wai.cabal
--- a/wai.cabal
+++ b/wai.cabal
@@ -1,5 +1,5 @@
 Name:                wai
-Version:             0.2.0
+Version:             0.2.1
 Synopsis:            Web Application Interface.
 Description:         Provides a common protocol for communication between web aplications and web servers.
 License:             BSD3