diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,20 @@
+Copyright (c) 2015 Sam Rijs
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/src/Control/Monad/Zipkin.hs b/src/Control/Monad/Zipkin.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Monad/Zipkin.hs
@@ -0,0 +1,28 @@
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+
+module Control.Monad.Zipkin
+  ( Identifier, parseIdentifier
+  , TraceInfo(..), fromHeaders, toHeaders, newTraceInfo
+  , TraceT, getTraceInfo, forkTraceInfo, runTraceT
+  ) where
+
+import Control.Monad.State.Strict
+import System.Random.Mersenne.Pure64
+
+import Data.Zipkin.Types
+import qualified Data.Zipkin.Context as Ctx
+
+newtype TraceT m a = TraceT { run :: StateT Ctx.TraceContext m a }
+  deriving (Functor, Applicative, Monad, MonadTrans)
+
+newTraceInfo :: IO TraceInfo
+newTraceInfo = evalState Ctx.newTraceInfo <$> newPureMT
+
+getTraceInfo :: Monad m => TraceT m TraceInfo
+getTraceInfo = TraceT Ctx.getTraceInfo
+
+forkTraceInfo :: Monad m => TraceT m TraceInfo
+forkTraceInfo = TraceT Ctx.forkTraceInfo
+
+runTraceT :: Monad m => TraceT m a -> TraceInfo -> m a
+runTraceT m = evalStateT (run m) . Ctx.mkContext
diff --git a/src/Data/Zipkin/Context.hs b/src/Data/Zipkin/Context.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Zipkin/Context.hs
@@ -0,0 +1,36 @@
+{-# LANGUAGE FlexibleContexts #-}
+
+module Data.Zipkin.Context where
+
+import Data.Bits (xor)
+import Control.Monad.State.Strict
+import System.Random.Mersenne.Pure64
+
+import Data.Zipkin.Types
+
+data TraceContext = TraceContext
+  { traceInfo :: TraceInfo
+  , traceGen :: PureMT
+  }
+
+mkContext :: TraceInfo -> TraceContext
+mkContext info = TraceContext
+  { traceInfo = info
+  , traceGen = pureMT $ hashTraceInfo info
+  }
+
+getTraceInfo :: MonadState TraceContext m => m TraceInfo
+getTraceInfo = gets traceInfo
+
+newTraceInfo :: MonadState PureMT m => m TraceInfo
+newTraceInfo = do
+  traceId <- Identifier <$> state randomWord64
+  spanId <- Identifier <$> state randomWord64
+  return $ TraceInfo traceId spanId Nothing
+
+forkTraceInfo :: MonadState TraceContext m => m TraceInfo
+forkTraceInfo = do
+  (TraceContext info gen) <- get
+  let (newId, gen') = randomWord64 gen
+  put (TraceContext info gen')
+  return $ TraceInfo (traceId info) (Identifier newId) (Just (spanId info))
diff --git a/src/Data/Zipkin/Types.hs b/src/Data/Zipkin/Types.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Zipkin/Types.hs
@@ -0,0 +1,48 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Data.Zipkin.Types where
+
+import Data.Bits (xor)
+import Data.ByteString (ByteString)
+import Data.ByteString.Char8 (pack, unpack)
+import Data.Maybe (maybeToList)
+import Data.String (IsString)
+import Data.Word (Word64)
+import Numeric (showHex, readHex)
+import Safe (readMay)
+import System.Random.Mersenne.Pure64
+
+newtype Identifier = Identifier { toWord64 :: Word64 }
+
+instance Show Identifier where
+  show (Identifier x) = let hex = showHex x "" in replicate (16 - length hex) '0' ++ hex
+
+instance Read Identifier where
+  readsPrec _ = fmap (fmap (\(x, s) -> (Identifier x, s))) readHex
+
+parseIdentifier :: String -> Maybe Identifier
+parseIdentifier = readMay
+
+data TraceInfo = TraceInfo
+  { traceId :: Identifier
+  , spanId :: Identifier
+  , parentSpanId :: Maybe Identifier
+  }
+
+hashTraceInfo :: TraceInfo -> Word64
+hashTraceInfo (TraceInfo traceId spanId parentSpanId) = maybe h (xor h . toWord64) parentSpanId
+  where h = toWord64 traceId `xor` toWord64 spanId
+
+fromHeaders :: (Eq s, IsString s) => [(s, ByteString)] -> Maybe TraceInfo
+fromHeaders hs = do
+  traceId <- lookup "X-B3-TraceId" hs >>= parseIdentifier . unpack
+  spanId <- lookup "X-B3-SpanId" hs >>= parseIdentifier . unpack
+  let parentSpanId = lookup "X-B3-ParentSpanId" hs >>= parseIdentifier . unpack
+  return $ TraceInfo traceId spanId parentSpanId
+
+toHeaders :: IsString s => TraceInfo -> [(s, ByteString)]
+toHeaders (TraceInfo traceId spanId parentSpanId) =
+  [ Just ("X-B3-TraceId", pack (show traceId))
+  , Just ("X-B3-SpanId", pack (show spanId))
+  , (\x -> ("X-B3-ParentSpanId", pack (show x))) <$> parentSpanId
+  ] >>= maybeToList
diff --git a/zipkin.cabal b/zipkin.cabal
new file mode 100644
--- /dev/null
+++ b/zipkin.cabal
@@ -0,0 +1,31 @@
+-- Initial trace-ids.cabal generated by cabal init.  For further 
+-- documentation, see http://haskell.org/cabal/users-guide/
+
+name:                zipkin
+version:             0.1.0.0
+synopsis:            Zipkin-style request tracing monad
+-- description:         
+homepage:            https://github.com/srijs/haskell-zipkin
+license:             MIT
+license-file:        LICENSE
+author:              Sam Rijs
+maintainer:          srijs@airpost.net
+-- copyright:           
+category:            Network
+build-type:          Simple
+-- extra-source-files:  
+cabal-version:       >=1.10
+
+library
+  exposed-modules:     Control.Monad.Zipkin
+  other-modules:       Data.Zipkin.Context
+                       Data.Zipkin.Types
+  -- other-modules:       
+  -- other-extensions:    
+  build-depends:       base >=4.8 && <4.9,
+                       bytestring >=0.10,
+                       mersenne-random-pure64 >=0.2,
+                       mtl >=2.2,
+                       safe >=0.3
+  hs-source-dirs:      src
+  default-language:    Haskell2010