diff --git a/free-http.cabal b/free-http.cabal
--- a/free-http.cabal
+++ b/free-http.cabal
@@ -1,6 +1,6 @@
 name:                free-http
 
-version:             0.1.1.3
+version:             0.2.0
 
 synopsis:            An HTTP Client based on Free Monads.
 
diff --git a/src/Network/HTTP/Client/Free.hs b/src/Network/HTTP/Client/Free.hs
--- a/src/Network/HTTP/Client/Free.hs
+++ b/src/Network/HTTP/Client/Free.hs
@@ -1,5 +1,6 @@
 {-| The primary Free Monad wrapping HTTP actions.
 -}
+{-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeFamilies #-}
 
 module Network.HTTP.Client.Free (
@@ -16,6 +17,10 @@
     -- ** A helpful type alias
     , FreeHttp
 
+    -- * Handy morphisms for working with HttpF
+    , natHttpF
+    , transHttp
+
     -- * smart constructors for http verbs
     , connect
     , delete
@@ -29,7 +34,7 @@
 
 ) where
 
-import Control.Monad.Trans.Free.Church (FT, liftF)
+import Control.Monad.Trans.Free.Church (FT, liftF, transFT)
 import Network.HTTP.Client (httpLbs, Manager, Request, Response)
 import Network.HTTP.Client.Free.Types (FreeHttp, HttpF(HttpF), RequestType, ResponseType)
 import Network.HTTP.Types.Method (StdMethod(..))
@@ -79,3 +84,19 @@
       => RequestType client
       -> FT (HttpF client) m (ResponseType client)
 patch req = liftF (HttpF PATCH req id)
+
+-- | A natural transformation between 'HttpF' types.
+natHttpF :: (RequestType client1 -> RequestType client2)
+        -> (ResponseType client2 -> ResponseType client1)
+        -> HttpF client1 a
+        -> HttpF client2 a
+natHttpF reqT respT (HttpF method req resp) = HttpF method (reqT req) (resp . respT)
+
+-- | 'transHttp' allows clients to mix-and-match http request and response
+-- foundations, so long as there is an appropriate morphism.
+transHttp :: Monad m
+          => (RequestType client1 -> RequestType client2)
+          -> (ResponseType client2 -> ResponseType client1)
+          -> FreeHttp client1 m a
+          -> FreeHttp client2 m a
+transHttp reqT respT = transFT (natHttpF reqT respT)
diff --git a/src/Network/HTTP/Client/Free/HttpClient.hs b/src/Network/HTTP/Client/Free/HttpClient.hs
--- a/src/Network/HTTP/Client/Free/HttpClient.hs
+++ b/src/Network/HTTP/Client/Free/HttpClient.hs
@@ -34,8 +34,10 @@
 -------------------------------------------------------------------------------
 -- | Peel a layer of the 'HttpF' functor and run an http request with the data
 -- provided.
-iterTHttp :: ( Request ~ RequestType client
-             , Response ByteString ~ ResponseType client
+iterTHttp :: ( Request ~ RequestType client 
+                -- The foundational request must be of type 'Request'
+             , Response ByteString ~ ResponseType client 
+                -- The foundational response must be of type 'Response ByteString'
              , Monad m
              , MonadIO m
              )
@@ -49,7 +51,9 @@
 -- | Peel a layer of the 'HttpF' functor and run an http request with the data.
 -- the base monad for this action is 't m'.
 iterTMHttp :: ( Request ~ RequestType client
+             -- The foundational request must be of type 'Request'
               , Response ByteString ~ ResponseType client
+             -- The foundational response must be of type 'Response ByteString'
               , Monad m
               , MonadTrans t
               , Monad (t m)
@@ -65,7 +69,9 @@
 -- | The main http-client interpreter. The client is free to specify the base
 -- effect monad so long as there is an instance of 'MonadIO' for it in scope.
 runHttp :: ( Request ~ RequestType client
+           -- The foundational request must be of type 'Request'
            , Response ByteString ~ ResponseType client
+           -- The foundational response must be of type 'Response ByteString'
            , Monad m
            , MonadIO m
            )
@@ -79,7 +85,9 @@
 -- effect monad ('m'), and in thise case this the result can be lifted into a
 -- higher monad transformer stack ('t')
 runTHttp :: ( Request ~ RequestType client
+            -- The foundational request must be of type 'Request'
             , Response ByteString ~ ResponseType client
+            -- The foundational response must be of type 'Response ByteString'
             , Monad m
             , MonadIO m
             , MonadTrans t