diff --git a/mongrel2-handler.cabal b/mongrel2-handler.cabal
--- a/mongrel2-handler.cabal
+++ b/mongrel2-handler.cabal
@@ -1,5 +1,5 @@
 Name:                mongrel2-handler
-Version:             0.3.0
+Version:             0.3.1
 Synopsis:            Mongrel2 Handler Library
 Description:         Mongrel2 Handler Library.
 
@@ -17,9 +17,9 @@
 
 Library
   Build-Depends: base             >= 4.0 && <5
-               , attoparsec       >= 0.8.5.0 && < 0.9
+               , attoparsec       >= 0.8.5.0 && < 0.10
                , blaze-builder    >= 0.3 && < 0.4
-               , blaze-textual    >= 0.1 && < 0.2
+               , blaze-textual    >= 0.1 && < 0.3
                , bytestring       >= 0.9.0.1
                , case-insensitive >= 0.2 && < 0.3
                , containers       >= 0.3 && < 0.5
diff --git a/src/Mongrel2.hs b/src/Mongrel2.hs
--- a/src/Mongrel2.hs
+++ b/src/Mongrel2.hs
@@ -6,17 +6,18 @@
        , receiveRequest
        , sendReply
        -- Re-exported
+       , buildResponse
+       , ClientID
        , Connection(..)
        , Request(..)
        , UUID
-       , ClientID
        ) where
 
 import Blaze.ByteString.Builder (Builder)
 import Data.Attoparsec
 import Mongrel2.Types (Connection(..), Request(..))
 import Mongrel2.Parser (messageParser, UUID, ClientID)
-import Mongrel2.Response (mkResponse)
+import Mongrel2.Response (buildResponse, mkResponse)
 import qualified System.ZMQ as ZMQ
 
 data Handler = Handler { handlerPullFrom :: String
diff --git a/src/Mongrel2/Response.hs b/src/Mongrel2/Response.hs
--- a/src/Mongrel2/Response.hs
+++ b/src/Mongrel2/Response.hs
@@ -1,5 +1,6 @@
 module Mongrel2.Response
        ( Response
+       , buildResponse
        , mkResponse
        ) where
 
@@ -10,7 +11,9 @@
 import Data.List (intersperse)
 import Data.Monoid
 import Mongrel2.Types (ClientID, UUID)
+import Network.HTTP.Types (Status(..), ResponseHeaders)
 import qualified Data.ByteString as S
+import qualified Data.CaseInsensitive as CI
 
 -- | Raw response type.
 type Response = ByteString
@@ -48,3 +51,27 @@
                          , buildNetstring $ buildClientIDList clientIDs
                          , fromByteString ", "
                          , bodyBuilder ]
+
+-- | Build a HTTP response.
+buildResponse :: Status -> ResponseHeaders -> ByteString -> Builder
+buildResponse status responseHeaders body =
+  mconcat [ fromByteString "HTTP/1.1 "
+          , integral $ statusCode status
+          , fromByteString " "
+          , fromByteString $ statusMessage status
+          , crlf
+          , mconcat $ map buildResponseHeader responseHeaders
+          , crlf
+          , fromByteString body
+          ]
+  where
+
+    buildResponseHeader (name,value) =
+      mconcat [ fromByteString $ CI.original name
+              , fromByteString ": "
+              , fromByteString value
+              , crlf
+              ]
+
+    crlf = fromByteString "\r\n"
+