diff --git a/scrobble.cabal b/scrobble.cabal
--- a/scrobble.cabal
+++ b/scrobble.cabal
@@ -1,5 +1,5 @@
 name:                scrobble
-version:             0.1.0.0
+version:             0.1.0.1
 synopsis:            Scrobbling server.
 description:         A library providing server-side support
                      for the Audioscrobbler Realtime Submission protocol:
@@ -20,6 +20,7 @@
 library
   hs-source-dirs:    src
   exposed-modules:   Scrobble.Server
+  other-modules:     Scrobble.Types
   build-depends:     base >4 && <5,
                      network,
                      url,
diff --git a/src/Scrobble/Types.hs b/src/Scrobble/Types.hs
new file mode 100644
--- /dev/null
+++ b/src/Scrobble/Types.hs
@@ -0,0 +1,99 @@
+-- | Scrobbling data types.
+
+module Scrobble.Types where
+
+import           Data.Time
+import           Network
+
+-- | Server configuration.
+data Config = Config
+  { cfgPort   :: PortNumber      -- ^ Port to listen on.
+  , cfgHost   :: String          -- ^ Host name used for server (probably just localhost).
+  , cfgExpire :: NominalDiffTime -- ^ Number of seconds of inactivity before a session expires.
+  } deriving (Show)
+
+-- | Event handlers.
+data Handlers = Handlers
+  { handleHandshake   :: Session -> IO ()                   -- ^ Initial connection hand-shake.
+  , handleExpire      :: Session -> IO ()                   -- ^ Session expiry.
+  , handleNowPlaying  :: Session -> NowPlaying -> IO ()     -- ^ Now-playing notification.
+  , handleSubmissions :: Session -> [Submission] -> IO Bool -- ^ Played tracks submission.
+  }
+
+-- | A scrobbling session.
+data Session = Session
+  { sesHandshake :: Bool    -- ^ Does the session require handshake?
+  , sesVersion   :: String  -- ^ Version of the protocol.
+  , sesClientId  :: String  -- ^ Client (music player's) id.
+  , sesClientVer :: String  -- ^ Client version.
+  , sesUser      :: String  -- ^ Username.
+  , sesTimestamp :: UTCTime -- ^ Timestamp of connection.
+  , sesToken     :: String  -- ^ Session token.
+  } deriving (Show)
+
+-- | A now playing track.
+data NowPlaying = NowPlaying
+  { npArtist      :: String        -- ^ Artist name.
+  , npTrack       :: String        -- ^ Track title.
+  , npAlbum       :: Maybe String  -- ^ Album name (if any).
+  , npLength      :: Maybe Integer -- ^ Track length in seconds (if known).
+  , npPosition    :: Maybe Integer -- ^ Track position (if known).
+  , npMusicBrainz :: Maybe String  -- ^ MusicBrainz track id (if known).
+  } deriving (Show)
+
+-- | A track submission.
+data Submission = Submission
+  { subArtist      :: String        -- ^ Artist name.
+  , subTrack       :: String        -- ^ Track title.
+  , subTimestamp   :: UTCTime       -- ^ Track timestamp.
+  , subSource      :: Source        -- ^ Source of track.
+  , subRating      :: Maybe Rating  -- ^ Rating (if any).
+  , subLength      :: Maybe Integer -- ^ Track length (if any).
+  , subAlbum       :: Maybe String  -- ^ Album (if any).
+  , subPosition    :: Maybe Integer -- ^ Track position in album (if any).
+  , subMusicBrainz :: Maybe String  -- ^ MusicBrainz track id (if any).
+  } deriving (Show)
+
+-- | A rating of a track.
+--
+-- Note: Currently, a web-service must also be called to set love/ban
+-- status. We anticipate that this will be phased out soon, and the
+-- submission service will handle the whole process.
+data Rating
+  = Love -- ^ Love (on any mode if the user has manually loved the
+         -- track). This implies a listen.
+
+  | Ban -- ^ Ban (only if source=L). This implies a skip, and the
+        -- client should skip to the next track when a ban happens.
+
+  | Skip -- ^ Skip (only if source=L).
+
+  deriving (Enum,Eq,Show,Read)
+
+-- | The source of the track. Required, must be one of the following
+-- codes:
+--
+-- Please note, for the time being, sources other than P and L are not
+-- supported.
+data Source
+  = UserChosen -- ^ Chosen by the user
+
+  | NonPersonlizedBroadcast -- ^ Non-personalised broadcast
+                            -- (e.g. Shoutcast, BBC Radio 1)
+
+  | Personalized -- ^ Personalised recommendation except Last.fm
+                 -- (e.g. Pandora, Launchcast)
+
+  | LastFm -- ^ Last.fm (any mode). In this case, the 5-digit Last.fm
+           -- recommendation key must be appended to this source ID to
+           -- prove the validity of the submission (for example,
+           -- "o[0]=L1b48a").
+
+  | Unknown -- ^ Source unknown.
+
+  deriving (Show,Enum,Eq,Read)
+
+
+-- | Server response.
+data Response = OK | BANNED | BADAUTH | FAILED String | BADSESSION
+  deriving Show