diff --git a/src/Network/Wai/Middleware/ContentType.hs b/src/Network/Wai/Middleware/ContentType.hs
--- a/src/Network/Wai/Middleware/ContentType.hs
+++ b/src/Network/Wai/Middleware/ContentType.hs
@@ -49,6 +49,8 @@
 import Data.Monoid
 import Control.Monad
 
+
+
 -- | Given an HTTP @Accept@ header and a content type to base lookups off of, and
 -- a map of responses, find a response.
 lookupFileExt :: Maybe AcceptHeader
@@ -59,13 +61,14 @@
     getFirst
   . foldMap (\fe -> First $ runResponseVia <$> HM.lookup fe m)
   . findFE
-  $ maybe allFileExts possibleFileExts mAcceptBS
+  $ maybe (HM.keys m) possibleFileExts mAcceptBS
   where
     findFE :: [FileExt] -> [FileExt]
     findFE xs =
       case mFe of
         Nothing -> xs
         Just fe -> fe <$ guard (fe `elem` xs)
+
 
 fileExtsToMiddleware :: Monad m => FileExtListenerT m a -> MiddlewareT m
 fileExtsToMiddleware xs app req respond = do
diff --git a/src/Network/Wai/Middleware/ContentType/Types.hs b/src/Network/Wai/Middleware/ContentType/Types.hs
--- a/src/Network/Wai/Middleware/ContentType/Types.hs
+++ b/src/Network/Wai/Middleware/ContentType/Types.hs
@@ -85,6 +85,7 @@
   | Json
   | Text
   | Markdown
+  | Other T.Text -- ^ incliding prefix period, i.e. `.foo`
   deriving (Show, Eq, Ord, Generic)
 
 instance Hashable FileExt
@@ -99,27 +100,31 @@
 getFileExt :: [T.Text] -> Maybe FileExt
 getFileExt chunks = case chunks of
   [] -> Nothing
-  xs -> toExt . snd . T.breakOn "." $ last xs
+  xs -> toExt . T.breakOnEnd "." $ last xs
 
 {-# INLINEABLE getFileExt #-}
 
 -- | matches a file extension (__including__ it's prefix dot - @.html@ for example)
 --   to a known one.
-toExt :: T.Text -> Maybe FileExt
-toExt x | x `elem` htmls       = Just Html
-        | x `elem` csss        = Just Css
-        | x `elem` javascripts = Just JavaScript
-        | x `elem` jsons       = Just Json
-        | x `elem` texts       = Just Text
-        | x `elem` markdowns   = Just Markdown
-        | otherwise            = Nothing
+toExt :: (T.Text, T.Text) -> Maybe FileExt
+toExt (y,x)
+  | x == ""
+    || T.length y == 0
+    || T.last y /= '.'   = Nothing
+  | x `elem` htmls       = Just Html
+  | x `elem` csss        = Just Css
+  | x `elem` javascripts = Just JavaScript
+  | x `elem` jsons       = Just Json
+  | x `elem` texts       = Just Text
+  | x `elem` markdowns   = Just Markdown
+  | otherwise            = Just $ Other x
   where
-    htmls       = [".htm", ".html"]
-    csss        = [".css"]
-    javascripts = [".js", ".javascript"]
-    jsons       = [".json"]
-    texts       = [".txt"]
-    markdowns   = [".md", ".markdown"]
+    htmls       = ["htm", "html"]
+    csss        = ["css"]
+    javascripts = ["js", "javascript"]
+    jsons       = ["json"]
+    texts       = ["txt"]
+    markdowns   = ["md", "markdown"]
 
 {-# INLINEABLE toExt #-}
 
@@ -127,7 +132,7 @@
 -- ayy, lamo. Basically.
 data ResponseVia = forall a. ResponseVia
   { responseData     :: !a
-  , responseStatus   :: !Status
+  , responseStatus   :: {-# UNPACK #-} !Status
   , responseHeaders  :: !ResponseHeaders
   , responseFunction :: !(a -> Status -> ResponseHeaders -> Response)
   }
@@ -215,16 +220,22 @@
   where
     computed :: [FileExt]
     computed = concat $
-      catMaybes [ mapAccept [ ("application/json"       :: BS.ByteString, [Json])
-                            , ("application/javascript" :: BS.ByteString, [JavaScript,Json])
+      catMaybes [ mapAccept [ ( "application/json"       :: BS.ByteString
+                              , [Json])
+                            , ( "application/javascript" :: BS.ByteString
+                              , [JavaScript,Json])
                             ] accept
-                , mapAccept [ ("text/html" :: BS.ByteString, [Html])
+                , mapAccept [ ( "text/html" :: BS.ByteString
+                              , [Html])
                             ] accept
-                , mapAccept [ ("text/plain" :: BS.ByteString, [Text, Markdown])
+                , mapAccept [ ( "text/plain" :: BS.ByteString
+                              , [Text, Markdown])
                             ] accept
-                , mapAccept [ ("text/markdown" :: BS.ByteString, [Markdown])
+                , mapAccept [ ( "text/markdown" :: BS.ByteString
+                              , [Markdown])
                             ] accept
-                , mapAccept [ ("text/css" :: BS.ByteString, [Css])
+                , mapAccept [ ( "text/css" :: BS.ByteString
+                              , [Css])
                             ] accept
                 ]
 
diff --git a/test/Network/Wai/Middleware/ContentTypeSpec.hs b/test/Network/Wai/Middleware/ContentTypeSpec.hs
--- a/test/Network/Wai/Middleware/ContentTypeSpec.hs
+++ b/test/Network/Wai/Middleware/ContentTypeSpec.hs
@@ -162,8 +162,8 @@
   fileExtsToMiddleware allExamples $
   (\req respond -> respond (textOnly "Something went wrong" status406 []))
 
-allExamples :: FileExtListenerT Response IO ()
-allExamples = mapResponse (\f -> f status200 []) $ do
+allExamples :: FileExtListenerT IO ()
+allExamples = do
   text "Text!"
   json ("Json!" :: T.Text)
   lucid (L.toHtmlRaw ("Html!" :: T.Text))
diff --git a/wai-middleware-content-type.cabal b/wai-middleware-content-type.cabal
--- a/wai-middleware-content-type.cabal
+++ b/wai-middleware-content-type.cabal
@@ -1,5 +1,5 @@
 Name:                   wai-middleware-content-type
-Version:                0.4.1
+Version:                0.5.0
 Author:                 Athan Clark <athan.clark@gmail.com>
 Maintainer:             Athan Clark <athan.clark@gmail.com>
 License:                BSD3
@@ -61,24 +61,12 @@
 Test-Suite test
   Type:                 exitcode-stdio-1.0
   Default-Language:     Haskell2010
-  HS-Source-Dirs:       src
-                      , test
+  HS-Source-Dirs:       test
   GHC-Options:          -Wall -threaded
   Main-Is:              Spec.hs
-  Other-Modules:        Network.Wai.Middleware.ContentType
-                        Network.Wai.Middleware.ContentType.Types
-                        Network.Wai.Middleware.ContentType.Blaze
-                        Network.Wai.Middleware.ContentType.ByteString
-                        Network.Wai.Middleware.ContentType.Cassius
-                        Network.Wai.Middleware.ContentType.Clay
-                        Network.Wai.Middleware.ContentType.Json
-                        Network.Wai.Middleware.ContentType.Julius
-                        Network.Wai.Middleware.ContentType.Lucid
-                        Network.Wai.Middleware.ContentType.Lucius
-                        Network.Wai.Middleware.ContentType.Pandoc
-                        Network.Wai.Middleware.ContentType.Text
-                        Network.Wai.Middleware.ContentTypeSpec
+  Other-Modules:        Network.Wai.Middleware.ContentTypeSpec
   Build-Depends:        base >= 4.8 && < 5
+                      , wai-middleware-content-type
                       , aeson
                       , blaze-builder
                       , blaze-html