diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Changelog for warp-grpc
 
+## 0.4.0.1
+
+Add the `grpc-encoding` header to the response ([#20](https://github.com/haskell-grpc-native/http2-grpc-haskell/pull/20)).
+
 ## 0.4.0.0
 
 Support for handlers in transformers stacks, and in monads which support [`unliftio`](http://hackage.haskell.org/package/unliftio).
diff --git a/src/Network/GRPC/Server/Wai.hs b/src/Network/GRPC/Server/Wai.hs
--- a/src/Network/GRPC/Server/Wai.hs
+++ b/src/Network/GRPC/Server/Wai.hs
@@ -95,12 +95,19 @@
                               , Handler $ \(e::SomeException) -> 
                                  modifyGRPCStatus r req (GRPCStatus INTERNAL $ ByteString.pack $ show e)
                               ]
-            in (rep $ responseStream status200 hdrs200 grpcHandler)
+            in (rep $ responseStream status200 (hdrs200 req) grpcHandler)
         Nothing ->
             app req rep
   where
-    hdrs200 = [
+    bestCompression req   = lookupEncoding req compressions
+    pickedCompression req = fromMaybe (Encoding uncompressed) (bestCompression req)
+
+    hopefulDecompression req = lookupDecoding req compressions
+    pickedDecompression req  = fromMaybe (Decoding uncompressed) (hopefulDecompression req)
+
+    hdrs200 req = [
         ("content-type", grpcContentTypeHV)
+      , ("grpc-encoding", grpcCompressionHV (_getEncodingCompression $ pickedCompression req))
       , ("trailer", CI.original grpcStatusH)
       , ("trailer", CI.original grpcMessageH)
       ]
@@ -108,15 +115,7 @@
     lookupHandler p plainHandlers = grpcWaiHandler <$>
         List.find (\(ServiceHandler rpcPath _) -> rpcPath == p) plainHandlers
     doHandle r handler req write flush = do
-        let bestCompression = lookupEncoding req compressions
-        let pickedCompression = fromMaybe (Encoding uncompressed) bestCompression
-
-        let hopefulDecompression = lookupDecoding req compressions
-        let pickedDecompression = fromMaybe (Decoding uncompressed) hopefulDecompression
-
-        putStrLn "running handler"
-        _ <- handler pickedDecompression pickedCompression req write flush
-        putStrLn "setting GRPC status"
+        _ <- handler (pickedDecompression req) (pickedCompression req) req write flush
         modifyGRPCStatus r req (GRPCStatus OK "WAI handler ended.")
 
 #if MIN_VERSION_warp(3,3,0)
diff --git a/warp-grpc.cabal b/warp-grpc.cabal
--- a/warp-grpc.cabal
+++ b/warp-grpc.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: e655a88509754d2322f32ede1f4ca7a39ab5ba25b54ef1d9f2e79ad6521ec110
+-- hash: 66d2a5fc66e9ca521d6751543a4205c207099d1cf7ace8c6fb84adc55cc1f32a
 
 name:           warp-grpc
-version:        0.4.0.0
+version:        0.4.0.1
 synopsis:       A minimal gRPC server on top of Warp.
 description:    Please see the README on Github at <https://github.com/haskell-grpc-native/http2-grpc-haskell/blob/master/warp-grpc/README.md>
 category:       Networking