diff --git a/Database/Cayley/Client.hs b/Database/Cayley/Client.hs
--- a/Database/Cayley/Client.hs
+++ b/Database/Cayley/Client.hs
@@ -1,4 +1,6 @@
-{-# LANGUAGE OverloadedStrings, FlexibleContexts, RecordWildCards #-}
+{-# LANGUAGE FlexibleContexts  #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards   #-}
 
 module Database.Cayley.Client (
       Quad (..)
@@ -19,23 +21,22 @@
     , isValid
     , successfulResults
     ) where
- 
-import Control.Applicative ((<|>))
-import Control.Lens.Fold ((^?))
-import Control.Monad.Catch
-import Control.Monad.Reader
-import qualified Data.Aeson as A
-import Data.Aeson.Lens (key)
-import qualified Data.Attoparsec.Text as AT
-import Data.Maybe (fromJust)
-import qualified Data.Text as T
-import Data.Text.Encoding (encodeUtf8)
-import Network.HTTP.Client
-import Network.HTTP.Client.MultipartFormData
 
-import Database.Cayley.Internal
-import Database.Cayley.Types
+import           Control.Applicative                   ((<|>))
+import           Control.Lens.Fold                     ((^?))
+import           Control.Monad.Catch
+import           Control.Monad.Reader
+import qualified Data.Aeson                            as A
+import           Data.Aeson.Lens                       (key)
+import qualified Data.Attoparsec.Text                  as AT
+import qualified Data.Text                             as T
+import           Data.Text.Encoding                    (encodeUtf8)
+import           Network.HTTP.Client
+import           Network.HTTP.Client.MultipartFormData
 
+import           Database.Cayley.Internal
+import           Database.Cayley.Types
+
 -- | Get a connection to Cayley with the given configuration.
 --
 -- >λ> conn <- connectCayley defaultCayleyConfig
@@ -53,7 +54,7 @@
 query c q =
     runReaderT (doQuery (getManager c) (encodeUtf8 q)) (getConfig c)
   where
-    doQuery m q = do
+    doQuery m _q = do
         CayleyConfig {..} <- ask
         r <- apiRequest
                  m ("http://"
@@ -62,7 +63,7 @@
                     ++ show apiVersion
                     ++ "/query/"
                     ++ show queryLang)
-                 serverPort (RequestBodyBS q)
+                 serverPort (RequestBodyBS _q)
         return $ case r of
             Just a  ->
                 case a ^? key "result" of
@@ -72,7 +73,7 @@
                           Just e  ->
                               case A.fromJSON e of
                                   A.Success s -> Left s
-                                  A.Error e   -> Left e
+                                  A.Error _e   -> Left _e
                           Nothing ->
                               Left "No JSON response from Cayley server"
             Nothing -> Left "Can't get any response from Cayley server"
@@ -105,24 +106,24 @@
 -- | Write the given list of 'Quad'(s).
 writeQuads :: CayleyConnection -> [Quad] -> IO (Maybe A.Value)
 writeQuads c qs =
-    runReaderT (write (getManager c) qs) (getConfig c)
+    runReaderT (_write (getManager c) qs) (getConfig c)
   where
-    write m qs = do
-        CayleyConfig {..} <- ask
-        apiRequest
-            m ("http://"
-               ++ serverName
-               ++ "/api/v"
-               ++ show apiVersion
-               ++ "/write")
-            serverPort (toRequestBody qs)
+    _write m _qs = do
+         CayleyConfig {..} <- ask
+         apiRequest
+             m ("http://"
+                ++ serverName
+                ++ "/api/v"
+                ++ show apiVersion
+                ++ "/write")
+             serverPort (toRequestBody _qs)
 
 -- | Delete the given list of 'Quad'(s).
 deleteQuads :: CayleyConnection -> [Quad] -> IO (Maybe A.Value)
 deleteQuads c qs =
-    runReaderT (delete (getManager c) qs) (getConfig c)
+    runReaderT (_delete (getManager c) qs) (getConfig c)
   where
-    delete m qs = do
+    _delete m _qs = do
         CayleyConfig {..} <- ask
         apiRequest
             m ("http://"
@@ -131,17 +132,21 @@
                ++ show apiVersion
                ++ "/delete")
             serverPort
-            (toRequestBody qs)
+            (toRequestBody _qs)
 
 -- | Write a N-Quad file.
 --
 -- >λ> writeNQuadFile conn "testdata.nq"
 -- >Just (Object (fromList [("result",String "Successfully wrote 11 quads.")]))
 --
+writeNQuadFile :: (MonadThrow m, MonadIO m)
+               => CayleyConnection
+               -> FilePath
+               -> m (Maybe A.Value)
 writeNQuadFile c p =
     runReaderT (writenq (getManager c) p) (getConfig c)
   where
-    writenq m p = do
+    writenq m _p = do
         CayleyConfig {..} <- ask
         r <- parseUrl ("http://"
                        ++ serverName
@@ -152,9 +157,9 @@
         t <- liftIO $
                  try $
                     flip httpLbs m
-                        =<< formDataBody [partFileSource "NQuadFile" p] r
+                        =<< formDataBody [partFileSource "NQuadFile" _p] r
         return $ case t of
-            Right r -> A.decode $ responseBody r
+            Right _r -> A.decode $ responseBody _r
             Left e  -> Just $
                 A.object ["error" A..= T.pack (show (e :: SomeException))]
 
@@ -185,7 +190,7 @@
                     case A.fromJSON v of
                         A.Success s ->
                             case AT.parse getAmount s of
-                                AT.Done "" a -> Right a
+                                AT.Done "" b -> Right b
                                 _            ->
                                     Left "Can't get amount of successful results"
                         A.Error e   -> Left e
@@ -194,13 +199,14 @@
                         Just e  ->
                             case A.fromJSON e of
                                 A.Success s -> Left s
-                                A.Error e   -> Left e
+                                A.Error r   -> Left r
                         Nothing -> Left "No JSON response from Cayley server"
         Nothing -> Left "Can't get any response from Cayley server"
   where
     getAmount = do
-        AT.string "Successfully "
-        AT.string "deleted " <|> AT.string "wrote "
+        _ <- AT.string "Successfully "
+        _ <- AT.string "deleted " <|> AT.string "wrote "
         a <- AT.decimal
-        AT.string " quads."
+        _ <- AT.string " quads."
         return a
+
diff --git a/Database/Cayley/Internal.hs b/Database/Cayley/Internal.hs
--- a/Database/Cayley/Internal.hs
+++ b/Database/Cayley/Internal.hs
@@ -1,17 +1,17 @@
 {-# LANGUAGE OverloadedStrings #-}
 
 module Database.Cayley.Internal where
- 
-import Control.Monad.Catch
-import Control.Monad.IO.Class
-import Control.Monad.Reader
-import qualified Data.Aeson as A
-import qualified Data.Text as T (pack)
-import Data.Vector (fromList)
-import Network.HTTP.Client
 
-import Database.Cayley.Types
+import           Control.Monad.Catch
+import           Control.Monad.IO.Class
+import           Control.Monad.Reader
+import qualified Data.Aeson             as A
+import qualified Data.Text              as T (pack)
+import           Data.Vector            (fromList)
+import           Network.HTTP.Client
 
+import           Database.Cayley.Types
+
 apiRequest :: Manager
            -> String
            -> Int
@@ -22,7 +22,7 @@
              return c { method = "POST", port = p, requestBody = b }
     t <- liftIO $ try $ httpLbs r m
     case t of
-        Right r -> return $ A.decode $ responseBody r
+        Right _r -> return $ A.decode $ responseBody _r
         Left  e ->
             return $
                 Just $
@@ -31,7 +31,9 @@
 toRequestBody :: [Quad] -> RequestBody
 toRequestBody qs = RequestBodyLBS $ A.encode $ fromList $ map A.toJSON qs
 
+getManager :: CayleyConnection -> Manager
 getManager (CayleyConnection (_,m)) = m
 
+getConfig :: CayleyConnection -> CayleyConfig
 getConfig (CayleyConnection (c,_)) = c
 
diff --git a/Database/Cayley/Types.hs b/Database/Cayley/Types.hs
--- a/Database/Cayley/Types.hs
+++ b/Database/Cayley/Types.hs
@@ -2,11 +2,10 @@
 
 module Database.Cayley.Types where
 
-import qualified Data.Aeson as A
-import Control.Applicative
-import Control.Monad
-import qualified Data.Text as T
-import Network.HTTP.Client (Manager)
+import           Control.Monad
+import qualified Data.Aeson          as A
+import qualified Data.Text           as T
+import           Network.HTTP.Client (Manager)
 
 data APIVersion = V1
 
@@ -27,6 +26,7 @@
     } deriving (Show)
 
 -- | CayleyConfig { serverPort = 64210 , serverName = "localhost" , apiVersion = V1 , queryLang  = Gremlin }
+defaultCayleyConfig :: CayleyConfig
 defaultCayleyConfig = CayleyConfig
     { serverPort = 64210
     , serverName = "localhost"
@@ -63,11 +63,11 @@
     Quad s p o l == Quad s' p' o' l' = s == s' && p == p' && o == o' && l == l'
 
 instance A.ToJSON Quad where
-    toJSON (Quad subject predicate object label) =
-        A.object [ "subject"   A..= subject
-                 , "predicate" A..= predicate
-                 , "object"    A..= object
-                 , "label"     A..= label
+    toJSON (Quad _subject _predicate _object _label) =
+        A.object [ "subject"   A..= _subject
+                 , "predicate" A..= _predicate
+                 , "object"    A..= _object
+                 , "label"     A..= _label
                  ]
 
 instance A.FromJSON Quad where
@@ -77,7 +77,7 @@
                              v A..: "object" <*>
                              v A..: "label"
     parseJSON _            = mzero
-     
+
 type Query = T.Text
 
 type Subject = T.Text
diff --git a/cayley-client.cabal b/cayley-client.cabal
--- a/cayley-client.cabal
+++ b/cayley-client.cabal
@@ -1,6 +1,5 @@
 name:                cayley-client
-version:             0.1.5.0
-stability:           Experimental
+version:             0.1.5.1
 synopsis:            A Haskell client for the Cayley graph database
 description:         cayley-client implements the RESTful API of the Cayley graph database.
 homepage:            https://github.com/MichelBoucey/cayley-client
@@ -8,7 +7,7 @@
 license-file:        LICENSE
 author:              Michel Boucey
 maintainer:          michel.boucey@gmail.com
-copyright:           Copyright © 2015-2016 - Michel Boucey
+copyright:           Copyright (c) 2015-2016 - Michel Boucey
 category:            Database
 build-type:          Simple
 cabal-version:       >=1.10
@@ -18,7 +17,23 @@
   Location: https://github.com/MichelBoucey/cayley-client.git
 
 library
-  exposed-modules:     Database.Cayley.Client, Database.Cayley.Types, Database.Cayley.Internal
+  exposed-modules:     Database.Cayley.Client
+                     , Database.Cayley.Types
+                     , Database.Cayley.Internal
   other-extensions:    OverloadedStrings
-  build-depends:       base >=4.7 && <=4.9, mtl >=2.1, transformers >=0.3, attoparsec >=0.12, bytestring >=0.10, text >=1.2, vector >=0.10, http-conduit >=2.1, http-client >=0.4, aeson >=0.8, lens >= 4.6.0.1, lens-aeson >=1.0.0.3, unordered-containers >=0.2, exceptions >= 0.6
+  build-depends:       base >=4.7 && <5
+                     , mtl >=2.1
+                     , transformers >=0.3
+                     , attoparsec >=0.12
+                     , bytestring >=0.10
+                     , text >=1.2
+                     , vector >=0.10
+                     , http-conduit >=2.1
+                     , http-client >=0.4
+                     , aeson >=0.8
+                     , lens >= 4.6.0.1
+                     , lens-aeson >=1.0.0.3
+                     , unordered-containers >=0.2
+                     , exceptions >= 0.6
   default-language:    Haskell2010
+  GHC-Options:    -Wall