diff --git a/example/snap.hs b/example/snap.hs
--- a/example/snap.hs
+++ b/example/snap.hs
@@ -1,26 +1,27 @@
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE CPP               #-}
-{-# LANGUAGE TemplateHaskell   #-}
+{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RankNTypes        #-}
+{-# LANGUAGE TemplateHaskell   #-}
 
 
 module Main where
 
 ------------------------------------------------------------------------------
+import           Control.Exception      (SomeException, try)
+import           Control.Lens           hiding (index)
 import           Control.Monad
-import           Control.Exception (SomeException, try)
-import           Data.ByteString (ByteString)
+import           Control.Monad.IO.Class
+import           Data.ByteString        (ByteString)
 import           Data.Maybe
-import           Prelude hiding ((.))
+import qualified Data.Text              as T
+import qualified Heist.Interpreted      as I
+import           Prelude                hiding ((.))
 import           Snap
-import           Snap.Snaplet.Heist
 import           Snap.Snaplet.Config
+import           Snap.Snaplet.Heist
 import           System.IO
-import qualified Data.Text as T
-import qualified Heist.Interpreted as I
-import Control.Lens hiding (value)
 
-import Snap.Snaplet.I18N
+import           Snap.Snaplet.I18N
 
 import           Snap.Loader.Static
 
@@ -28,8 +29,8 @@
 ------------------------------------------------------------------------------
 
 data App = App
-    { _heist   :: Snaplet (Heist App)
-    , _i18n   :: Snaplet I18N
+    { _heist :: Snaplet (Heist App)
+    , _i18n  :: Snaplet I18N
     }
 
 makeLenses ''App
@@ -52,13 +53,12 @@
 
 testSplice :: I.Splice AppHandler
 testSplice = do
-    locale <- liftIO $ getDefaultLocale
+    locale <- liftIO getDefaultLocale
     liftIO $ print locale
     I.textSplice $ T.pack "test"
 
 index :: AppHandler ()
-index = do
-     heistLocal (I.bindSplice "testSplice" testSplice) $ render "index"
+index = heistLocal (I.bindSplice "testSplice" testSplice) $ render "index"
 
 -- | wrap to element span
 --
@@ -75,14 +75,14 @@
 app :: SnapletInit App App
 app = makeSnaplet "app" "An snaplet example application." Nothing $ do
     h <- nestSnaplet "heist" heist $ heistInit "templates"
-    --locale <- liftIO $ getDefaultLocale
-    i <- nestSnaplet "i18n" i18n $ initI18N (Just "zh_CN")
+    locale <- liftIO getDefaultLocale
+    i <- nestSnaplet "i18n" i18n $ initI18N locale
     addRoutes routes
     return $ App h i
 
-getDefaultLocale :: IO (Maybe String)
+getDefaultLocale :: IO (Maybe Locale)
 --getDefaultLocale = return $ Just "zh_CN"
-getDefaultLocale = liftM getLocale getConf
+getDefaultLocale = fmap getLocale getConf
 
 ------------------------------------------------------------------------------
 
@@ -92,7 +92,7 @@
                                           'getActions
                                           ["heist/templates"])
 
-    _ <- try $ httpServe conf $ site :: IO (Either SomeException ())
+    _ <- try $ httpServe conf site :: IO (Either SomeException ())
     cleanup
 
 getConf :: IO (Config Snap AppConfig)
diff --git a/snaplet-i18n.cabal b/snaplet-i18n.cabal
--- a/snaplet-i18n.cabal
+++ b/snaplet-i18n.cabal
@@ -1,9 +1,5 @@
--- snaplet-i10n.cabal auto-generated by cabal init. For additional
--- options, see
--- http://www.haskell.org/cabal/release/cabal-latest/doc/users-guide/authors.html#pkg-descr.
--- The name of the package.
 Name:                snaplet-i18n
-Version:             0.0.5
+Version:             0.1.0
 Description:         A light weight i18n snaplet.
 Synopsis:            snaplet-i18n
 Homepage:            https://github.com/HaskellCNOrg/snaplet-i18n
@@ -17,7 +13,7 @@
 Stability:           Experience
 Cabal-version:       >=1.10
 
-Extra-source-files:  
+Extra-source-files:
   README.md
   example/snap.hs
   snaplets/heist/templates/*.tpl
@@ -31,47 +27,49 @@
 Library
   Hs-Source-Dirs:   src
   default-language:    Haskell2010
-  Exposed-modules:     
+  Exposed-modules:
       Snap.Snaplet.I18N
 
   Other-modules: Paths_snaplet_i18n
 
-  Build-Depends:    
-      base         >= 4       && < 5,
-      configurator >= 0.2     && < 0.3,
-      filepath     >= 1.2     && < 1.4,
-      heist        >= 0.10    && < 0.14,
-      lens         >= 3.7.0.1 && < 3.8,
-      snap         >= 0.10    && < 0.14,
-      snap-loader-static >= 0.9 && < 0.11,
-      text         >= 0.11    && < 1.2,
-      xmlhtml      >= 0.2
+  Build-Depends:
+                base         >= 4       && < 5
+              , mtl
+              , transformers
+              , configurator
+              , filepath
+              , heist
+              , lens
+              , snap
+              , snap-loader-static
+              , text
+              , xmlhtml
 
   if impl(ghc >= 6.12.0)
       ghc-options: -Wall -fwarn-tabs -funbox-strict-fields
                    -fno-warn-orphans -fno-warn-unused-do-bind
   else
       ghc-options: -Wall -fwarn-tabs -funbox-strict-fields
-                   -fno-warn-orphans     
+                   -fno-warn-orphans
 
 Executable demo
-  Hs-Source-Dirs:   example
-  default-language:    Haskell2010
-  main-is: snap.hs
-
-  Build-Depends:    
-      base         >= 4       && < 5,
-      configurator >= 0.2     && < 0.3,
-      filepath     >= 1.2     && < 1.4,
-      heist        >= 0.10    && < 0.14,
-      lens         >= 3.7.0.1 && < 3.8,
-      snap         >= 0.10    && < 0.14,
-      snap-loader-static >= 0.9 && < 0.11,
-      text         >= 0.11    && < 1.2,
-      xmlhtml      >= 0.2,
+  --Hs-Source-Dirs:   example
+  default-language: Haskell2010
+  main-is: example/snap.hs
 
-      bytestring   >= 0.9 && < 1.0,
-      snaplet-i18n
+  Build-Depends:
+                base         >= 4       && < 5
+              , configurator
+              , transformers
+              , filepath
+              , heist
+              , lens
+              , snap
+              , snap-loader-static
+              , text
+              , xmlhtml
+              , bytestring
+              , snaplet-i18n
 
   if impl(ghc >= 6.12.0)
       ghc-options: -Wall -fwarn-tabs -funbox-strict-fields
diff --git a/src/Snap/Snaplet/I18N.hs b/src/Snap/Snaplet/I18N.hs
--- a/src/Snap/Snaplet/I18N.hs
+++ b/src/Snap/Snaplet/I18N.hs
@@ -5,12 +5,16 @@
   ( I18N
   , HasI18N (..)
   , I18NMessage (..)
+  , Locale
+  , MessageFile
+
   , initI18N
   , getI18NMessages
   , lookupI18NValue
   ) where
 
-import           Control.Monad
+import           Control.Monad.IO.Class
+import           Control.Monad.State
 import qualified Data.Configurator       as Config
 import qualified Data.Configurator.Types as Config
 import           Data.Maybe
@@ -66,12 +70,12 @@
 -- | Util functions
 --
 getI18N :: HasI18N b => Handler b b I18N
-getI18N = with i18nLens Snap.get
+getI18N = with i18nLens get
 
 -- | Get the @I18NMessage@
 --
 getI18NMessages :: HasI18N b => Handler b b I18NMessage
-getI18NMessages = liftM _getI18NMessage getI18N
+getI18NMessages = fmap _getI18NMessage getI18N
 
 -- | Look up a value in, usuallly Handler Monad
 --
@@ -100,7 +104,7 @@
                   "i18n" ## i18nSplice
                   "i18nSpan" ## i18nSpanSplice
         -- config dir for current snaplet
-        datadir = Just $ liftM (++ "/resources") getDataDir
+        datadir = Just $ fmap (++ "/resources") getDataDir
         description = "light weight i18n snaplet"