diff --git a/datadog-tracing.cabal b/datadog-tracing.cabal
--- a/datadog-tracing.cabal
+++ b/datadog-tracing.cabal
@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                datadog-tracing
-version:             1.3.1
+version:             1.3.2
 synopsis:            Datadog tracing client and mock agent.
 license:             BSD-3-Clause
 license-file:        LICENSE
@@ -50,10 +50,10 @@
                     , Datadog.Jaeger
   other-modules:      Data.MessagePack.Aeson
                     , Servant.MsgPack
-  build-depends:    , data-msgpack    ^>= 0.0.12
-                    , ffunctor        ^>= 1.1.0
+  build-depends:    , ffunctor        ^>= 1.1.0
                     , generic-random  ^>= 1.2.0.0
                     , http-media      ^>= 0.7.1.3
+                    , msgpack         ^>= 1.0.1.0
                     , refined         ^>= 0.2.3.0 || ^>= 0.4
                     , prettyprinter   ^>= 1.2.1
                     , servant-client  ^>= 0.14
diff --git a/exe/Main.hs b/exe/Main.hs
--- a/exe/Main.hs
+++ b/exe/Main.hs
@@ -30,7 +30,9 @@
 postTraces3 r t = (\_ -> NoContent) <$> postTraces4 r t
 
 postTraces4 :: IORef [Trace] -> [Trace] -> Handler TraceResponse
-postTraces4 ref traces = liftIO $ (atomicModifyIORef' ref update)
+postTraces4 ref traces = do
+  liftIO . putStrLn $ "received " <> show (length traces) <> " traces"
+  liftIO $ (atomicModifyIORef' ref update)
   where update store = ((reverse traces) <> store, TraceResponse M.empty)
 
 getTraces :: IORef [Trace] -> Handler Jaeger
diff --git a/library/Data/MessagePack/Aeson.hs b/library/Data/MessagePack/Aeson.hs
--- a/library/Data/MessagePack/Aeson.hs
+++ b/library/Data/MessagePack/Aeson.hs
@@ -2,11 +2,7 @@
 --   http://hackage.haskell.org/package/msgpack-aeson-0.1.0.0/docs/src/Data-MessagePack-Aeson.html#toAeson
 --   with only minor changes to use the data-msgpack fork (mostly changing Vector to list).
 
-{-# LANGUAGE DeriveDataTypeable         #-}
-{-# LANGUAGE DeriveFunctor              #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE LambdaCase                 #-}
-{-# LANGUAGE ViewPatterns               #-}
+{-# LANGUAGE LambdaCase #-}
 
 -- | Aeson bridge for MessagePack
 --
@@ -14,14 +10,15 @@
 module Data.MessagePack.Aeson where
 
 import           Control.Arrow
-import           Data.Aeson          as A
-import qualified Data.HashMap.Strict as HM
-import           Data.MessagePack    as MP
+import           Data.Aeson           as A
+import           Data.ByteString.Lazy (ByteString)
+import qualified Data.HashMap.Strict  as HM
+import           Data.MessagePack     as MP
 import           Data.Scientific
-import qualified Data.Text.Encoding  as T
-import qualified Data.Vector         as V
+import qualified Data.Text.Encoding   as T
+import qualified Data.Vector          as V
 
-toAeson :: (Monad m) => MP.Object -> m Value
+toAeson :: MP.Object -> A.Result Value
 toAeson = \case
   ObjectNil      -> pure Null
   ObjectBool b   -> pure . Bool $ b
@@ -30,11 +27,12 @@
   ObjectDouble d -> pure . Number $ realToFrac d
   ObjectStr t    -> pure . String $ t
   ObjectBin b    -> String <$> either (fail . show) pure (T.decodeUtf8' b)
-  ObjectArray (V.fromList -> v)  -> Array <$> V.mapM toAeson v
-  ObjectMap (m)    ->
-    A.Object . HM.fromList <$> mapM (\(k, v) -> (,) <$> fromObject k <*> toAeson v) m
-  ObjectExt _ _  -> fail "ObjectExt not supported"
-  ObjectWord _ -> fail "ObjectWord not supported"
+  ObjectArray v  -> Array <$> V.mapM toAeson v
+  ObjectMap m    ->
+    A.Object . HM.fromList . V.toList
+      <$> V.mapM (\(k, v) -> (,) <$> from k <*> toAeson v) m
+      where from = maybe (fail "bad object") pure . MP.fromObject
+  ObjectExt _ _  -> fail "ObjectExt is not supported"
 
 fromAeson :: Value -> MP.Object
 fromAeson = \case
@@ -45,5 +43,11 @@
       Left f  -> ObjectDouble f
       Right n -> ObjectInt n
   String t    -> ObjectStr t
-  Array (V.toList -> v)     -> ObjectArray $ map fromAeson v
-  A.Object (HM.toList -> o)  -> ObjectMap $ map (toObject *** fromAeson) o
+  Array v     -> ObjectArray $ V.map fromAeson v
+  A.Object o  -> ObjectMap $ V.fromList $ map (toObject *** fromAeson) $ HM.toList o
+
+packToJSON :: ToJSON a => a -> ByteString
+packToJSON = pack . fromAeson . toJSON
+
+unpackFromJSON :: FromJSON a => ByteString -> Result a
+unpackFromJSON b = fromJSON =<< toAeson =<< maybe (fail "msgpack") pure (unpack b)
diff --git a/library/Datadog/Client.hs b/library/Datadog/Client.hs
--- a/library/Datadog/Client.hs
+++ b/library/Datadog/Client.hs
@@ -25,11 +25,12 @@
   , Trace(..)
   , TraceId(..)
   , newServantAgent
+  , newServantAgent'
 ) where
 
 import           Control.Monad             (unless, void)
 import           Control.Monad.Except      (ExceptT, MonadError, MonadIO,
-                                            liftEither, liftIO)
+                                            liftEither, liftIO, runExceptT)
 import           Data.Char                 (isAlpha, isAsciiLower, isDigit)
 import           Data.FFunctor             (FFunctor, ffmap)
 import           Data.Int                  (Int64)
@@ -69,6 +70,12 @@
 -- | An Agent (or AgentT) implemented by Servant.
 newServantAgent :: (MonadIO m, MonadError ServantError m) => ClientEnv -> Agent m
 newServantAgent env = ffmap (liftClientM env) (Agent traces)
+
+-- | A fire-and-forget Agent implemented by Servant.
+newServantAgent' :: MonadIO m => ClientEnv -> Agent m
+newServantAgent' env =
+  let agent = newServantAgent env
+  in Agent (\t -> void . runExceptT $ putTraces agent t)
 
 type DDText = Refined.NonEmpty && (SizeLessThan 101)
 
diff --git a/library/Servant/MsgPack.hs b/library/Servant/MsgPack.hs
--- a/library/Servant/MsgPack.hs
+++ b/library/Servant/MsgPack.hs
@@ -11,7 +11,6 @@
 
 import           Data.Aeson
 import           Data.List.NonEmpty
-import           Data.MessagePack         (pack, unpack)
 import           Data.MessagePack.Aeson
 import           Network.HTTP.Media       ((//))
 import           Servant.API.ContentTypes
@@ -24,9 +23,9 @@
                             , "application" // "vnd.msgpack"]
 
 instance ToJSON a => MimeRender MsgPack a where
-  mimeRender _ = pack . fromAeson . toJSON
+  mimeRender _ = packToJSON
 
 instance FromJSON a => MimeUnrender MsgPack a where
-  mimeUnrender _ b = case fromJSON =<< toAeson =<< unpack b of
-    Error str -> Left str
-    Success a -> Right a
+  mimeUnrender _ b = case unpackFromJSON b of
+      Error str -> Left str
+      Success a -> Right a