diff --git a/hzulip.cabal b/hzulip.cabal
--- a/hzulip.cabal
+++ b/hzulip.cabal
@@ -1,5 +1,5 @@
 name:                hzulip
-version:             0.2.0.0
+version:             0.2.0.1
 synopsis:            A haskell wrapper for the Zulip API.
 description:         This a Zulip API wrapper for Haskell.
 homepage:            https://github.com/yamadapc/hzulip
@@ -14,6 +14,7 @@
 
 library
   exposed-modules:     HZulip
+  other-modules:       HZulip.Types
   build-depends:       base >=4.7 && <4.8
                      , wreq >=0.2 && <0.3
                      , lens >=4.4 && <4.5
diff --git a/src/HZulip/Types.hs b/src/HZulip/Types.hs
new file mode 100644
--- /dev/null
+++ b/src/HZulip/Types.hs
@@ -0,0 +1,138 @@
+{-# LANGUAGE OverloadedStrings #-}
+module HZulip.Types where
+
+import Control.Applicative ((<$>), (<*>), pure)
+import Control.Monad (mzero)
+import Data.Aeson
+
+-- |
+-- Represents a Zulip API client
+data ZulipClient = ZulipClient { clientEmail   :: String
+                               , clientApiKey  :: String
+                               , clientBaseUrl :: String
+                               }
+
+-- |
+-- The internal response representation for top-down parsing of Zulip API
+-- JSON responses
+data Response = Response { responseResult      :: ResponseResult
+                         , responseMsg         :: String
+
+                         , responseMessageId   :: Maybe String
+                         , responseQueueId     :: Maybe String
+                         , responseLastEventId :: Maybe Int
+
+                         , responseEvents      :: Maybe [Event]
+                         }
+
+instance FromJSON Response where
+    parseJSON (Object o) = Response <$>
+                           o .:  "result"        <*>
+                           o .:  "msg"           <*>
+                           o .:? "id"            <*>
+                           o .:? "queue_id"      <*>
+                           o .:? "last_event_id" <*>
+                           o .:? "events"
+    parseJSON _ = mzero
+
+-- |
+-- Represnts a response result, this is just so result Strings aren't
+-- modeled in memory
+data ResponseResult = ResponseError | ResponseSuccess
+  deriving(Eq, Show, Ord)
+
+
+instance FromJSON ResponseResult where
+    parseJSON (String "success") = pure ResponseSuccess
+    parseJSON _                  = pure ResponseError
+
+-- |
+-- Represents zulip events
+data Event = Event { eventType    :: String
+                   , eventId      :: String
+                   , eventMessage :: Maybe Message
+                   }
+
+instance FromJSON Event where
+    parseJSON (Object o) = Event <$>
+                           o .: "type"     <*>
+                           o .:  "id"      <*>
+                           o .:? "message"
+    parseJSON _ = mzero
+
+-- |
+-- Represents a Zulip Message
+data Message = Message { messageId               :: String
+                       , messageType             :: String
+                       , messageContent          :: String
+
+                       , messageAvatarUrl        :: String
+                       , messageTimestamp        :: Int
+
+                       , messageDisplayRecipient :: Either String [User]
+
+                       , messageSender           :: User
+
+                       , messageGravatarHash     :: String
+
+                       , messageRecipientId      :: String
+                       , messageClient           :: String
+                       , messageSubjectLinks     :: [String]
+                       , messageSubject          :: String
+                       }
+
+instance FromJSON Message where
+    parseJSON (Object o) = Message <$>
+                           o .: "id"                <*>
+                           o .: "type"              <*>
+                           o .: "content"           <*>
+
+                           o .: "avatar_url"        <*>
+                           o .: "timestamp"         <*>
+
+                           o .: "display_recipient" <*>
+
+                           (User <$>
+                             o .: "sender_full_name"  <*>
+                             o .: "sender_domain"     <*>
+                             o .: "sender_email"      <*>
+                             o .: "sender_short_name" <*>
+                             o .: "sender_id"
+                           ) <*>
+
+                           o .: "gravatar_hash"     <*>
+
+                           o .: "recipient_id"      <*>
+                           o .: "client"            <*>
+                           o .: "subject_links"     <*>
+                           o .: "subject"
+    parseJSON _ = mzero
+
+-- |
+-- Represents a zulip user account - for both `display_recipient` and
+-- `message_sender` representations
+data User = User { userId        :: String
+                 , userFullName  :: String
+                 , userEmail     :: String
+                 , userDomain    :: String
+                 , userShortName :: String
+                 }
+
+instance FromJSON User where
+    parseJSON (Object o) = User <$>
+                           o .: "full_name"  <*>
+                           o .: "domain"     <*>
+                           o .: "email"      <*>
+                           o .: "short_name" <*>
+                           o .: "id"
+    parseJSON _ = mzero
+
+-- |
+-- Represents some event queue
+data Queue = Queue { queueId     :: String
+                   , lastEventId :: Int
+                   }
+
+-- |
+-- The root type for Event callbacks
+type EventCallback = Event -> IO ()