diff --git a/src/Web/Users/Persistent.hs b/src/Web/Users/Persistent.hs
--- a/src/Web/Users/Persistent.hs
+++ b/src/Web/Users/Persistent.hs
@@ -1,25 +1,18 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE EmptyDataDecls #-}
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE GADTs #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE QuasiQuotes #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE TypeFamilies  #-}
-{-# LANGUAGE TypeSynonymInstances #-}
 module Web.Users.Persistent (LoginId, Persistent(..)) where
 
 import Web.Users.Types
+import Web.Users.Persistent.Definitions
 
-import Control.Applicative ((<$>), (<|>))
+import Control.Applicative ((<|>))
 import Control.Monad
+import Control.Monad.Trans.Maybe
 import Control.Monad.Reader
 #if MIN_VERSION_mtl(2,2,0)
 import Control.Monad.Except
@@ -31,38 +24,11 @@
 import Data.Time.Clock
 import Database.Persist
 import Database.Persist.Sql
-import Database.Persist.TH
-import qualified Data.ByteString.Char8 as BSC
 import qualified Data.ByteString.Lazy as BSL
 import qualified Data.Text as T
 import qualified Data.UUID as UUID
 import qualified Data.UUID.V4 as UUID
 
-share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
-Login
-    createdAt UTCTime
-    username T.Text
-    email T.Text
-    password T.Text
-    active Bool
-    more BSC.ByteString
-    UniqueUsername username
-    UniqueEmail email
-    deriving Show
-    deriving Eq
-    deriving Typeable
-LoginToken
-    token T.Text
-    tokenType T.Text
-    createdAt UTCTime
-    validUntil UTCTime
-    owner LoginId
-    UniqueToken token
-    UniqueTypedToken token tokenType
-    deriving Show
-    deriving Eq
-    deriving Typeable
-|]
 
 #if MIN_VERSION_base(4,7,0)
 deriving instance Typeable Key
@@ -162,24 +128,27 @@
               do now <- getCurrentTime
                  let usr = mkUser now
                  runPersistent conn $
-                   do mFst <- selectFirst ([LoginUsername ==. loginUsername usr] ||. [LoginEmail ==. loginEmail usr]) []
-                      case mFst of
-                        Just _ -> return $ Left UsernameOrEmailAlreadyTaken
-                        Nothing -> Right <$> insert usr
+                   do mUsername <- selectFirst [LoginUsername ==. loginUsername usr] []
+                      mEmailAddress <- selectFirst [LoginEmail ==. loginEmail usr] []
+                      case (mUsername, mEmailAddress) of
+                        (Just _, Just _)   -> return $ Left UsernameAndEmailAlreadyTaken
+                        (Just _, _)        -> return $ Left UsernameAlreadyTaken
+                        (Nothing, Just _)  -> return $ Left EmailAlreadyTaken
+                        (Nothing, Nothing) -> Right <$> insert usr
     updateUser conn userId updateFun =
         do mUser <- getUserById conn userId
            case mUser of
              Nothing ->
-                 return $ Left UserDoesntExit
+                 return $ Left UserDoesntExist
              Just origUser ->
                  runErrorT $
                  do let newUser = updateFun origUser
                     when (u_name newUser /= u_name origUser) $
                          do counter <- liftIO $ runPersistent conn $ count [LoginUsername ==. u_name newUser]
-                            when (counter /= 0) $ throwError UsernameOrEmailAlreadyExists
+                            when (counter /= 0) $ throwError UsernameAlreadyExists
                     when (u_email newUser /= u_email origUser) $
                          do counter <- liftIO $ runPersistent conn $ count [LoginEmail ==. u_email newUser]
-                            when (counter /= 0) $ throwError UsernameOrEmailAlreadyExists
+                            when (counter /= 0) $ throwError EmailAlreadyExists
                     liftIO $ runPersistent conn $
                        do update userId [ LoginUsername =. u_name newUser, LoginEmail =. u_email newUser, LoginActive =. u_active newUser
                                         , LoginMore =. (BSL.toStrict $ encode $ u_more newUser) ]
@@ -189,15 +158,12 @@
     deleteUser conn userId =
         runPersistent conn $ delete userId
     withAuthUser conn userOrEmail authFn action =
-        runPersistent conn $
-        do mFst <- selectFirst ([LoginUsername ==. userOrEmail] ||. [LoginEmail ==. userOrEmail]) []
-           case mFst of
-             Nothing -> return Nothing
-             Just login ->
-                 do user <- unpackLogin' (entityVal login)
-                    if authFn user
-                    then liftIO $ Just <$> action (entityKey login)
-                    else return Nothing
+      runMaybeT $
+      do login <- MaybeT . liftIO . runPersistent conn
+                $ selectFirst ([LoginUsername ==. userOrEmail] ||. [LoginEmail ==. userOrEmail]) []
+         user <- unpackLogin' $ entityVal login
+         guard $ authFn user
+         liftIO . action . entityKey $ login
     authUser conn userOrEmail pwd sessionTtl =
         withAuthUser conn userOrEmail (\(user :: User Value) -> verifyPassword pwd $ u_password user) $ \userId ->
             SessionId <$> createToken conn "session" userId sessionTtl
@@ -208,6 +174,11 @@
              Just userId ->
                  do extendToken conn "session" sessionId extendTime
                     return (Just userId)
+    createSession conn userId sessionTtl =
+        do mUser <- getUserById conn userId
+           case (mUser :: Maybe (User Value)) of
+             Nothing -> return Nothing
+             Just _ -> Just . SessionId <$> createToken conn "session" userId sessionTtl
     destroySession conn (SessionId sessionId) = deleteToken conn "session" sessionId
     requestPasswordReset conn userId timeToLive =
         do token <- createToken conn "password_reset" userId timeToLive
diff --git a/src/Web/Users/Persistent/Definitions.hs b/src/Web/Users/Persistent/Definitions.hs
new file mode 100644
--- /dev/null
+++ b/src/Web/Users/Persistent/Definitions.hs
@@ -0,0 +1,48 @@
+{-# LANGUAGE EmptyDataDecls #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeFamilies  #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+
+module Web.Users.Persistent.Definitions where
+
+import Database.Persist.TH
+import Data.Time.Clock
+import Data.Typeable
+import qualified Data.ByteString.Char8 as BSC
+import qualified Data.Text as T
+
+share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
+Login
+    createdAt UTCTime
+    username T.Text
+    email T.Text
+    password T.Text
+    active Bool
+    more BSC.ByteString
+    UniqueUsername username
+    UniqueEmail email
+    deriving Show
+    deriving Eq
+    deriving Typeable
+LoginToken
+    token T.Text
+    tokenType T.Text
+    createdAt UTCTime
+    validUntil UTCTime
+    owner LoginId
+    UniqueToken token
+    UniqueTypedToken token tokenType
+    deriving Show
+    deriving Eq
+    deriving Typeable
+|]
diff --git a/users-persistent.cabal b/users-persistent.cabal
--- a/users-persistent.cabal
+++ b/users-persistent.cabal
@@ -1,5 +1,5 @@
 name:                users-persistent
-version:             0.3.0.0
+version:             0.4.0.0
 synopsis:            A persistent backend for the users package
 description:         This library is a backend driver using <http://hackage.haskell.org/package/persistent persistent> for
                      <http://hackage.haskell.org/package/users the "users" library>.
@@ -28,10 +28,12 @@
 
 library
   exposed-modules:     Web.Users.Persistent
+                       Web.Users.Persistent.Definitions
   build-depends:       base >=4.6 && <5,
                        persistent >=2.0,
                        persistent-template >=2.1,
-                       users >=0.3,
+                       users >=0.4,
+                       transformers >=0.4,
                        mtl >=2.1,
                        aeson >=0.7,
                        time >=1.4,