diff --git a/demo-client/Demo/Client/API/Core/Greeter.hs b/demo-client/Demo/Client/API/Core/Greeter.hs
index 6747ce41..8448324c 100644
--- a/demo-client/Demo/Client/API/Core/Greeter.hs
+++ b/demo-client/Demo/Client/API/Core/Greeter.hs
@@ -11,8 +11,9 @@ import Network.GRPC.Common.Protobuf
 
 import Demo.Client.Util.DelayOr (DelayOr)
 import Demo.Client.Util.DelayOr qualified as DelayOr
-import Demo.Common.API
-import Demo.Common.Logging
+import Demo.Client.Util.Logging
+
+import Proto.API.Helloworld
 
 {-------------------------------------------------------------------------------
   helloworld.Greeter
diff --git a/demo-client/Demo/Client/API/Core/NoFinal/Greeter.hs b/demo-client/Demo/Client/API/Core/NoFinal/Greeter.hs
index bb5a1708..9351f02e 100644
--- a/demo-client/Demo/Client/API/Core/NoFinal/Greeter.hs
+++ b/demo-client/Demo/Client/API/Core/NoFinal/Greeter.hs
@@ -6,7 +6,7 @@ import Network.GRPC.Client
 import Network.GRPC.Common
 import Network.GRPC.Common.Protobuf
 
-import Demo.Common.API
+import Proto.API.Helloworld
 
 {-------------------------------------------------------------------------------
   helloworld.Greeter
diff --git a/demo-client/Demo/Client/API/Core/RouteGuide.hs b/demo-client/Demo/Client/API/Core/RouteGuide.hs
index 9819dde1..1ba01ec9 100644
--- a/demo-client/Demo/Client/API/Core/RouteGuide.hs
+++ b/demo-client/Demo/Client/API/Core/RouteGuide.hs
@@ -6,8 +6,9 @@ import Network.GRPC.Client
 import Network.GRPC.Common
 import Network.GRPC.Common.Protobuf
 
-import Demo.Common.API
-import Demo.Common.Logging
+import Demo.Client.Util.Logging
+
+import Proto.API.RouteGuide
 
 {-------------------------------------------------------------------------------
   RouteGuide
diff --git a/demo-client/Demo/Client/API/StreamType/Conduit/RouteGuide.hs b/demo-client/Demo/Client/API/StreamType/Conduit/RouteGuide.hs
index 3f368469..51479639 100644
--- a/demo-client/Demo/Client/API/StreamType/Conduit/RouteGuide.hs
+++ b/demo-client/Demo/Client/API/StreamType/Conduit/RouteGuide.hs
@@ -14,8 +14,9 @@ import Network.GRPC.Common.Protobuf
 
 import Demo.Client.Util.DelayOr (DelayOr)
 import Demo.Client.Util.DelayOr qualified as DelayOr
-import Demo.Common.API
-import Demo.Common.Logging
+import Demo.Client.Util.Logging
+
+import Proto.API.RouteGuide
 
 {-------------------------------------------------------------------------------
   routeguide.RouteGuide
diff --git a/demo-client/Demo/Client/API/StreamType/IO/Greeter.hs b/demo-client/Demo/Client/API/StreamType/IO/Greeter.hs
index 11d8e34d..ceb07513 100644
--- a/demo-client/Demo/Client/API/StreamType/IO/Greeter.hs
+++ b/demo-client/Demo/Client/API/StreamType/IO/Greeter.hs
@@ -8,8 +8,9 @@ import Network.GRPC.Client.StreamType.IO
 import Network.GRPC.Common.NextElem qualified as NextElem
 import Network.GRPC.Common.Protobuf
 
-import Demo.Common.API
-import Demo.Common.Logging
+import Demo.Client.Util.Logging
+
+import Proto.API.Helloworld
 
 {-------------------------------------------------------------------------------
   helloworld.Greeter
diff --git a/demo-client/Demo/Client/API/StreamType/IO/Ping.hs b/demo-client/Demo/Client/API/StreamType/IO/Ping.hs
index 3f49b4f1..b1ffe930 100644
--- a/demo-client/Demo/Client/API/StreamType/IO/Ping.hs
+++ b/demo-client/Demo/Client/API/StreamType/IO/Ping.hs
@@ -1,13 +1,12 @@
 module Demo.Client.API.StreamType.IO.Ping (ping) where
 
-import Data.ByteString.Lazy.Char8 qualified as Lazy
-
 import Network.GRPC.Client
 import Network.GRPC.Client.StreamType.IO
+import Network.GRPC.Common.Protobuf
 
-import Demo.Common.API
+import Proto.API.Ping
 
-ping :: Connection -> Lazy.ByteString -> IO ()
+ping :: Connection -> Proto PingMessage -> IO ()
 ping conn msg = do
     pong <- nonStreaming conn (rpc @Ping) msg
-    Lazy.putStrLn pong
+    print pong
diff --git a/demo-client/Demo/Client/API/StreamType/IO/RouteGuide.hs b/demo-client/Demo/Client/API/StreamType/IO/RouteGuide.hs
index 37e28f18..1974db34 100644
--- a/demo-client/Demo/Client/API/StreamType/IO/RouteGuide.hs
+++ b/demo-client/Demo/Client/API/StreamType/IO/RouteGuide.hs
@@ -15,8 +15,9 @@ import Network.GRPC.Common.Protobuf
 
 import Demo.Client.Util.DelayOr (DelayOr)
 import Demo.Client.Util.DelayOr qualified as DelayOr
-import Demo.Common.API
-import Demo.Common.Logging
+import Demo.Client.Util.Logging
+
+import Proto.API.RouteGuide
 
 {-------------------------------------------------------------------------------
   routeguide.RouteGuide
diff --git a/demo-client/Demo/Client/API/StreamType/MonadStack/Greeter.hs b/demo-client/Demo/Client/API/StreamType/MonadStack/Greeter.hs
index ea979bec..1955d0f1 100644
--- a/demo-client/Demo/Client/API/StreamType/MonadStack/Greeter.hs
+++ b/demo-client/Demo/Client/API/StreamType/MonadStack/Greeter.hs
@@ -13,8 +13,9 @@ import Network.GRPC.Client.StreamType.CanCallRPC
 import Network.GRPC.Common.NextElem qualified as NextElem
 import Network.GRPC.Common.Protobuf
 
-import Demo.Common.API
-import Demo.Common.Logging qualified as Logging
+import Demo.Client.Util.Logging qualified as Logging
+
+import Proto.API.Helloworld
 
 {-------------------------------------------------------------------------------
   Example custom monad
diff --git a/demo-client/Demo/Client/Cmdline.hs b/demo-client/Demo/Client/Cmdline.hs
index ec0832a1..74ab23fb 100644
--- a/demo-client/Demo/Client/Cmdline.hs
+++ b/demo-client/Demo/Client/Cmdline.hs
@@ -16,7 +16,6 @@ module Demo.Client.Cmdline (
 
 import Prelude
 
-import Data.ByteString.Lazy qualified as Lazy (ByteString)
 import Data.Foldable (asum)
 import Data.Int
 import Data.Kind
@@ -35,7 +34,11 @@ import Network.GRPC.Common.Protobuf
 import Paths_grapesy
 
 import Demo.Client.Util.DelayOr (DelayOr(..))
-import Demo.Common.API
+
+import Proto.API.Helloworld
+import Proto.API.Ping
+import Proto.API.RouteGuide
+import Text.Read (readMaybe)
 
 {-------------------------------------------------------------------------------
   Definition
@@ -75,7 +78,7 @@ data SMethod :: Type -> Type where
   SRecordRoute  :: [DelayOr (Proto Point)]     -> SMethod RecordRoute
   SRouteChat    :: [DelayOr (Proto RouteNote)] -> SMethod RouteChat
 
-  SPing :: Lazy.ByteString -> SMethod Ping
+  SPing :: Proto PingMessage -> SMethod Ping
 
 deriving stock instance Show (SMethod rpc)
 
@@ -249,7 +252,7 @@ parseSomeMethod = Opt.subparser $ mconcat [
           Opt.many (parseDelayOr $ parseRouteNote)
     , sub "ping" "Ping.ping" $
         SomeMethod . SPing <$>
-          Opt.argument Opt.str (Opt.metavar "MSG")
+          Opt.argument parsePingMessage (Opt.metavar "NUM")
     ]
 
 {-------------------------------------------------------------------------------
@@ -324,6 +327,15 @@ parseRouteNote =
           & #location .~ location
           & #message  .~ message
 
+parsePingMessage :: Opt.ReadM (Proto PingMessage)
+parsePingMessage = Opt.str >>= aux
+  where
+    aux :: String -> Opt.ReadM (Proto PingMessage)
+    aux str =
+        case readMaybe str of
+          Nothing  -> fail $ "Could not parse ping ID " ++ show str
+          Just pid -> return $ defMessage & #id .~ pid
+
 {-------------------------------------------------------------------------------
   Internal auxiliary
 -------------------------------------------------------------------------------}
diff --git a/demo-common/Demo/Common/Logging.hs b/demo-client/Demo/Client/Util/Logging.hs
similarity index 93%
rename from demo-common/Demo/Common/Logging.hs
rename to demo-client/Demo/Client/Util/Logging.hs
index 7e329aff..8b1939b8 100644
--- a/demo-common/Demo/Common/Logging.hs
+++ b/demo-client/Demo/Client/Util/Logging.hs
@@ -1,4 +1,4 @@
-module Demo.Common.Logging (
+module Demo.Client.Util.Logging (
     threadSafeTracer
   , logMsg
   ) where
diff --git a/demo-server/Demo/Server/Service/Greeter.hs b/demo-server/Demo/Server/Service/Greeter.hs
index 43fa4851..48098b22 100644
--- a/demo-server/Demo/Server/Service/Greeter.hs
+++ b/demo-server/Demo/Server/Service/Greeter.hs
@@ -13,7 +13,7 @@ import Network.GRPC.Server
 import Network.GRPC.Server.Protobuf
 import Network.GRPC.Server.StreamType
 
-import Demo.Common.API
+import Proto.API.Helloworld
 
 {-------------------------------------------------------------------------------
   Top-level
diff --git a/demo-server/Demo/Server/Service/Ping.hs b/demo-server/Demo/Server/Service/Ping.hs
index 71503aa4..212c99e2 100644
--- a/demo-server/Demo/Server/Service/Ping.hs
+++ b/demo-server/Demo/Server/Service/Ping.hs
@@ -1,16 +1,17 @@
-module Demo.Server.Service.Ping (handlers) where
+{-# LANGUAGE OverloadedLabels #-}
 
-import Data.ByteString.Lazy qualified as Lazy (ByteString)
+module Demo.Server.Service.Ping (handlers) where
 
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Server.StreamType
 
-import Demo.Common.API
+import Proto.API.Ping
 
 handlers :: Methods IO '[Ping]
 handlers =
       Method (mkNonStreaming handlePing)
     $ NoMoreMethods
 
-handlePing :: Lazy.ByteString -> IO Lazy.ByteString
-handlePing = return
+handlePing :: Proto PingMessage -> IO (Proto PongMessage)
+handlePing ping = return $ defMessage & #id .~ (ping ^. #id)
 
diff --git a/demo-server/Demo/Server/Service/RouteGuide.hs b/demo-server/Demo/Server/Service/RouteGuide.hs
index 29489325..03cc6866 100644
--- a/demo-server/Demo/Server/Service/RouteGuide.hs
+++ b/demo-server/Demo/Server/Service/RouteGuide.hs
@@ -8,6 +8,7 @@ module Demo.Server.Service.RouteGuide (
   ) where
 
 import Control.Monad.IO.Class
+import Control.Monad.Trans.Reader
 import Control.Monad.Trans.State (StateT, evalStateT)
 import Control.Monad.Trans.State qualified as State
 import Data.Map qualified as Map
@@ -21,10 +22,10 @@ import Network.GRPC.Server
 import Network.GRPC.Server.Protobuf
 import Network.GRPC.Server.StreamType
 
-import Demo.Common.API
 import Demo.Server.Aux.RouteGuide
 import Demo.Server.Cmdline
-import Control.Monad.Trans.Reader
+
+import Proto.API.RouteGuide
 
 {-------------------------------------------------------------------------------
   Custom handler monad
diff --git a/demo-server/Main.hs b/demo-server/Main.hs
index 95d246cf..4eced14d 100644
--- a/demo-server/Main.hs
+++ b/demo-server/Main.hs
@@ -12,14 +12,16 @@ import Network.GRPC.Server.Protobuf
 import Network.GRPC.Server.Run
 import Network.GRPC.Server.StreamType
 
+import Paths_grapesy
+
 import Demo.Server.Cmdline
 import Demo.Server.Service.Greeter    qualified as Greeter
 import Demo.Server.Service.Ping       qualified as Ping
 import Demo.Server.Service.RouteGuide qualified as RouteGuide
 
-import Demo.Common.API
-
-import Paths_grapesy
+import Proto.API.Helloworld
+import Proto.API.Ping
+import Proto.API.RouteGuide
 
 {-------------------------------------------------------------------------------
   All services
diff --git a/grapesy.cabal b/grapesy.cabal
index ed18f34e..6a11227b 100644
--- a/grapesy.cabal
+++ b/grapesy.cabal
@@ -177,7 +177,6 @@ library
       Paths_grapesy
 
       Proto.OrcaLoadReport
-      Proto.OrcaLoadReport_Fields
 
       Control.Monad.XIO
   autogen-modules:
@@ -316,8 +315,11 @@ test-suite test-grapesy
 
       Paths_grapesy
 
+      Proto.API.Interop
+      Proto.API.Ping
       Proto.Empty
       Proto.Messages
+      Proto.Ping
       Proto.Test
   autogen-modules:
       Paths_grapesy
@@ -359,7 +361,6 @@ executable demo-client
     , common-executable-flags
   hs-source-dirs:
       demo-client
-      demo-common
       proto
   main-is:
       Main.hs
@@ -374,16 +375,16 @@ executable demo-client
       Demo.Client.API.StreamType.MonadStack.Greeter
       Demo.Client.Cmdline
       Demo.Client.Util.DelayOr
-
-      Demo.Common.API
-      Demo.Common.Logging
+      Demo.Client.Util.Logging
 
       Paths_grapesy
 
+      Proto.API.Helloworld
+      Proto.API.Ping
+      Proto.API.RouteGuide
       Proto.Helloworld
-      Proto.Helloworld_Fields
+      Proto.Ping
       Proto.RouteGuide
-      Proto.RouteGuide_Fields
   autogen-modules:
       Paths_grapesy
   build-depends:
@@ -412,7 +413,6 @@ executable demo-server
     , common-executable-flags
   hs-source-dirs:
       demo-server
-      demo-common
       proto
   main-is:
       Main.hs
@@ -423,13 +423,12 @@ executable demo-server
       Demo.Server.Service.Ping
       Demo.Server.Service.RouteGuide
 
-      Demo.Common.API
-      Demo.Common.Logging
-
+      Proto.API.Helloworld
+      Proto.API.Ping
+      Proto.API.RouteGuide
       Proto.Helloworld
-      Proto.Helloworld_Fields
+      Proto.Ping
       Proto.RouteGuide
-      Proto.RouteGuide_Fields
 
       Paths_grapesy
   autogen-modules:
@@ -442,7 +441,6 @@ executable demo-server
     , aeson                >= 1.5  && < 2.3
     , bytestring           >= 0.10 && < 0.13
     , containers           >= 0.6  && < 0.8
-    , contra-tracer        >= 0.2  && < 0.3
     , exceptions           >= 0.10 && < 0.11
     , network              >= 3.1  && < 3.3
     , optparse-applicative >= 0.16 && < 0.19
@@ -493,7 +491,6 @@ test-suite grapesy-interop
   main-is:
       Main.hs
   other-modules:
-      Interop.API
       Interop.Client
       Interop.Client.Common
       Interop.Client.Connect
@@ -532,9 +529,11 @@ test-suite grapesy-interop
 
       Paths_grapesy
 
-      Proto.Ping
+      Proto.API.Interop
+      Proto.API.Ping
       Proto.Empty
       Proto.Messages
+      Proto.Ping
       Proto.Test
   autogen-modules:
       Paths_grapesy
diff --git a/interop/Interop/Client/Common.hs b/interop/Interop/Client/Common.hs
index 3e8da05c..a6b4d856 100644
--- a/interop/Interop/Client/Common.hs
+++ b/interop/Interop/Client/Common.hs
@@ -19,12 +19,14 @@ import Data.ByteString qualified as BS.Strict
 import Network.GRPC.Client
 import Network.GRPC.Common
 import Network.GRPC.Common.Compression qualified as Compr
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Util.Exceptions
 import Interop.Util.Messages
 
+import Proto.API.Interop
+
 {-------------------------------------------------------------------------------
   Config
 -------------------------------------------------------------------------------}
diff --git a/interop/Interop/Client/Ping.hs b/interop/Interop/Client/Ping.hs
index 3739f607..110cbdac 100644
--- a/interop/Interop/Client/Ping.hs
+++ b/interop/Interop/Client/Ping.hs
@@ -10,12 +10,11 @@ import Network.GRPC.Client.StreamType.IO
 import Network.GRPC.Common
 import Network.GRPC.Common.Protobuf
 
-import Proto.Ping
-
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 
+import Proto.API.Ping
+
 ping :: Cmdline -> IO ()
 ping cmdline =
     withConnection def (testServer cmdline) $ \conn ->
diff --git a/interop/Interop/Client/TestCase/CancelAfterBegin.hs b/interop/Interop/Client/TestCase/CancelAfterBegin.hs
index ba14513c..f65fb76a 100644
--- a/interop/Interop/Client/TestCase/CancelAfterBegin.hs
+++ b/interop/Interop/Client/TestCase/CancelAfterBegin.hs
@@ -3,11 +3,12 @@ module Interop.Client.TestCase.CancelAfterBegin (runTest) where
 import Network.GRPC.Client
 import Network.GRPC.Common
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#cancel_after_begin>
 --
 -- This is not really testing anything about the server, but rather about how
diff --git a/interop/Interop/Client/TestCase/CancelAfterFirstResponse.hs b/interop/Interop/Client/TestCase/CancelAfterFirstResponse.hs
index 9bde7695..3c138391 100644
--- a/interop/Interop/Client/TestCase/CancelAfterFirstResponse.hs
+++ b/interop/Interop/Client/TestCase/CancelAfterFirstResponse.hs
@@ -2,13 +2,15 @@ module Interop.Client.TestCase.CancelAfterFirstResponse (runTest) where
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 import Interop.Client.Common (mkStreamingOutputCallRequest)
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#cancel_after_first_response>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/ClientCompressedStreaming.hs b/interop/Interop/Client/TestCase/ClientCompressedStreaming.hs
index 2bbd9ed6..fec43731 100644
--- a/interop/Interop/Client/TestCase/ClientCompressedStreaming.hs
+++ b/interop/Interop/Client/TestCase/ClientCompressedStreaming.hs
@@ -2,14 +2,16 @@ module Interop.Client.TestCase.ClientCompressedStreaming (runTest) where
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#client_compressed_streaming>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/ClientCompressedUnary.hs b/interop/Interop/Client/TestCase/ClientCompressedUnary.hs
index 92e10178..26b394bb 100644
--- a/interop/Interop/Client/TestCase/ClientCompressedUnary.hs
+++ b/interop/Interop/Client/TestCase/ClientCompressedUnary.hs
@@ -6,11 +6,12 @@ import Network.GRPC.Client
 import Network.GRPC.Common
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#client_compressed_unary>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/ClientStreaming.hs b/interop/Interop/Client/TestCase/ClientStreaming.hs
index 6c50cb2f..64d536fe 100644
--- a/interop/Interop/Client/TestCase/ClientStreaming.hs
+++ b/interop/Interop/Client/TestCase/ClientStreaming.hs
@@ -2,13 +2,15 @@ module Interop.Client.TestCase.ClientStreaming (runTest) where
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 import Interop.Util.Messages
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#client_streaming>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/CustomMetadata.hs b/interop/Interop/Client/TestCase/CustomMetadata.hs
index 745ec7d3..a567298f 100644
--- a/interop/Interop/Client/TestCase/CustomMetadata.hs
+++ b/interop/Interop/Client/TestCase/CustomMetadata.hs
@@ -7,13 +7,15 @@ import Data.ByteString qualified as Strict (ByteString)
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#custom_metadata>
 --
 -- For both UnaryCall and FullDuplexCall, the reference server (at least some)
diff --git a/interop/Interop/Client/TestCase/EmptyStream.hs b/interop/Interop/Client/TestCase/EmptyStream.hs
index a0135810..00a054b0 100644
--- a/interop/Interop/Client/TestCase/EmptyStream.hs
+++ b/interop/Interop/Client/TestCase/EmptyStream.hs
@@ -5,10 +5,11 @@ import Control.Monad
 import Network.GRPC.Client
 import Network.GRPC.Common
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#empty_stream>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/EmptyUnary.hs b/interop/Interop/Client/TestCase/EmptyUnary.hs
index f430378e..724f48b1 100644
--- a/interop/Interop/Client/TestCase/EmptyUnary.hs
+++ b/interop/Interop/Client/TestCase/EmptyUnary.hs
@@ -4,14 +4,16 @@ import Data.Proxy
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Common.StreamElem qualified as StreamElem
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#empty_unary>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/LargeUnary.hs b/interop/Interop/Client/TestCase/LargeUnary.hs
index ca39dceb..19f149cb 100644
--- a/interop/Interop/Client/TestCase/LargeUnary.hs
+++ b/interop/Interop/Client/TestCase/LargeUnary.hs
@@ -3,12 +3,14 @@ module Interop.Client.TestCase.LargeUnary (runTest) where
 import Network.GRPC.Client
 import Network.GRPC.Client.StreamType.IO
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#large_unary>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/PingPong.hs b/interop/Interop/Client/TestCase/PingPong.hs
index 28a709f4..4a4ce766 100644
--- a/interop/Interop/Client/TestCase/PingPong.hs
+++ b/interop/Interop/Client/TestCase/PingPong.hs
@@ -4,12 +4,14 @@ import Control.Monad
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#ping_pong>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/ServerCompressedStreaming.hs b/interop/Interop/Client/TestCase/ServerCompressedStreaming.hs
index 076f96d9..6e0f5512 100644
--- a/interop/Interop/Client/TestCase/ServerCompressedStreaming.hs
+++ b/interop/Interop/Client/TestCase/ServerCompressedStreaming.hs
@@ -4,13 +4,14 @@ import Data.Maybe (isJust)
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
-import Network.GRPC.Spec
+
+import Proto.API.Interop
 
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#server_compressed_streaming>
 runTest :: Cmdline -> IO ()
diff --git a/interop/Interop/Client/TestCase/ServerCompressedUnary.hs b/interop/Interop/Client/TestCase/ServerCompressedUnary.hs
index 881f10de..0fee743e 100644
--- a/interop/Interop/Client/TestCase/ServerCompressedUnary.hs
+++ b/interop/Interop/Client/TestCase/ServerCompressedUnary.hs
@@ -4,16 +4,18 @@ import Data.Maybe (isJust)
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Common.StreamElem qualified as StreamElem
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 import Interop.Util.Messages
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#server_compressed_unary>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/ServerStreaming.hs b/interop/Interop/Client/TestCase/ServerStreaming.hs
index 9b9d2b06..b37c6c3d 100644
--- a/interop/Interop/Client/TestCase/ServerStreaming.hs
+++ b/interop/Interop/Client/TestCase/ServerStreaming.hs
@@ -3,11 +3,12 @@ module Interop.Client.TestCase.ServerStreaming (runTest) where
 import Network.GRPC.Client
 import Network.GRPC.Common
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#server_streaming>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/SpecialStatusMessage.hs b/interop/Interop/Client/TestCase/SpecialStatusMessage.hs
index 964a4806..c9e03824 100644
--- a/interop/Interop/Client/TestCase/SpecialStatusMessage.hs
+++ b/interop/Interop/Client/TestCase/SpecialStatusMessage.hs
@@ -6,13 +6,15 @@ import Data.Text (Text)
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#special_status_message>
 runTest :: Cmdline -> IO ()
 runTest cmdline = do
diff --git a/interop/Interop/Client/TestCase/StatusCodeAndMessage.hs b/interop/Interop/Client/TestCase/StatusCodeAndMessage.hs
index ee91afa8..ae9e05e3 100644
--- a/interop/Interop/Client/TestCase/StatusCodeAndMessage.hs
+++ b/interop/Interop/Client/TestCase/StatusCodeAndMessage.hs
@@ -6,13 +6,15 @@ import Data.Text (Text)
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#status_code_and_message>
 runTest :: Cmdline -> IO ()
 runTest cmdline = do
diff --git a/interop/Interop/Client/TestCase/TimeoutOnSleepingServer.hs b/interop/Interop/Client/TestCase/TimeoutOnSleepingServer.hs
index 69944a83..772a8cc6 100644
--- a/interop/Interop/Client/TestCase/TimeoutOnSleepingServer.hs
+++ b/interop/Interop/Client/TestCase/TimeoutOnSleepingServer.hs
@@ -2,13 +2,15 @@ module Interop.Client.TestCase.TimeoutOnSleepingServer (runTest) where
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 
-import Interop.API
 import Interop.Client.Common
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#timeout_on_sleeping_server>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/UnimplementedMethod.hs b/interop/Interop/Client/TestCase/UnimplementedMethod.hs
index 6ae6b700..bb413ef8 100644
--- a/interop/Interop/Client/TestCase/UnimplementedMethod.hs
+++ b/interop/Interop/Client/TestCase/UnimplementedMethod.hs
@@ -2,13 +2,15 @@ module Interop.Client.TestCase.UnimplementedMethod (runTest) where
 
 import Network.GRPC.Client
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Client.StreamType.IO
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#unimplemented_method>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Client/TestCase/UnimplementedService.hs b/interop/Interop/Client/TestCase/UnimplementedService.hs
index 20354bda..437f9920 100644
--- a/interop/Interop/Client/TestCase/UnimplementedService.hs
+++ b/interop/Interop/Client/TestCase/UnimplementedService.hs
@@ -5,11 +5,12 @@ import Network.GRPC.Common
 import Network.GRPC.Common.Protobuf
 import Network.GRPC.Client.StreamType.IO
 
-import Interop.API
 import Interop.Client.Connect
 import Interop.Cmdline
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 -- | <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#unimplemented_service>
 runTest :: Cmdline -> IO ()
 runTest cmdline =
diff --git a/interop/Interop/Server.hs b/interop/Interop/Server.hs
index 652655e7..f1f5a805 100644
--- a/interop/Interop/Server.hs
+++ b/interop/Interop/Server.hs
@@ -13,7 +13,6 @@ import Network.GRPC.Server.Protobuf
 import Network.GRPC.Server.Run
 import Network.GRPC.Server.StreamType
 
-import Interop.API
 import Interop.Cmdline
 
 import Interop.Server.PingService.Ping                qualified as Ping
@@ -23,6 +22,9 @@ import Interop.Server.TestService.StreamingInputCall  qualified as StreamingInpu
 import Interop.Server.TestService.StreamingOutputCall qualified as StreamingOutputCall
 import Interop.Server.TestService.UnaryCall           qualified as UnaryCall
 
+import Proto.API.Interop
+import Proto.API.Ping
+
 {-------------------------------------------------------------------------------
   Handlers
 
diff --git a/interop/Interop/Server/Common.hs b/interop/Interop/Server/Common.hs
index c1bfda02..aa89027e 100644
--- a/interop/Interop/Server/Common.hs
+++ b/interop/Interop/Server/Common.hs
@@ -10,12 +10,14 @@ module Interop.Server.Common (
 import Control.Exception
 
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Server
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 {-------------------------------------------------------------------------------
   Dealing with the test-suite's message types
 -------------------------------------------------------------------------------}
diff --git a/interop/Interop/Server/TestService/EmptyCall.hs b/interop/Interop/Server/TestService/EmptyCall.hs
index 0c275ef0..7b531a74 100644
--- a/interop/Interop/Server/TestService/EmptyCall.hs
+++ b/interop/Interop/Server/TestService/EmptyCall.hs
@@ -1,6 +1,8 @@
 module Interop.Server.TestService.EmptyCall (handle) where
 
-import Interop.API
+import Network.GRPC.Common.Protobuf
+
+import Proto.API.Interop
 
 -- | Handle @TestService.EmptyCall@
 --
diff --git a/interop/Interop/Server/TestService/FullDuplexCall.hs b/interop/Interop/Server/TestService/FullDuplexCall.hs
index 8cc0ee09..0df59c78 100644
--- a/interop/Interop/Server/TestService/FullDuplexCall.hs
+++ b/interop/Interop/Server/TestService/FullDuplexCall.hs
@@ -1,12 +1,14 @@
 module Interop.Server.TestService.FullDuplexCall (handle) where
 
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Server
 
-import Interop.API
 import Interop.Server.Common
 import Interop.Server.TestService.StreamingOutputCall qualified as StreamingOutputCall
 
+import Proto.API.Interop
+
 -- | Handle @TestService.FullDuplexCall@
 --
 -- <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#fullduplexcall>
diff --git a/interop/Interop/Server/TestService/StreamingInputCall.hs b/interop/Interop/Server/TestService/StreamingInputCall.hs
index ffcae8ea..d501774a 100644
--- a/interop/Interop/Server/TestService/StreamingInputCall.hs
+++ b/interop/Interop/Server/TestService/StreamingInputCall.hs
@@ -5,12 +5,14 @@ module Interop.Server.TestService.StreamingInputCall (handle) where
 import Data.ByteString qualified as BS.Strict
 
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Server
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Server.Common
 
+import Proto.API.Interop
+
 -- | Handle @TestService.StreamingInputCall@
 --
 -- <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#streaminginputcall>
diff --git a/interop/Interop/Server/TestService/StreamingOutputCall.hs b/interop/Interop/Server/TestService/StreamingOutputCall.hs
index 3d4e22ec..b468d9f2 100644
--- a/interop/Interop/Server/TestService/StreamingOutputCall.hs
+++ b/interop/Interop/Server/TestService/StreamingOutputCall.hs
@@ -7,12 +7,14 @@ import Control.Concurrent
 import Control.Monad
 
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Server
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Util.Messages
 
+import Proto.API.Interop
+
 -- | Handle @TestService.StreamingOutputCall@
 --
 -- <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#streamingoutputcall>
diff --git a/interop/Interop/Server/TestService/UnaryCall.hs b/interop/Interop/Server/TestService/UnaryCall.hs
index 39602d2c..4e7aff1e 100644
--- a/interop/Interop/Server/TestService/UnaryCall.hs
+++ b/interop/Interop/Server/TestService/UnaryCall.hs
@@ -3,14 +3,16 @@
 module Interop.Server.TestService.UnaryCall (handle) where
 
 import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
 import Network.GRPC.Common.StreamElem qualified as StreamElem
 import Network.GRPC.Server
 import Network.GRPC.Spec
 
-import Interop.API
 import Interop.Server.Common
 import Interop.Util.Messages
 
+import Proto.API.Interop
+
 -- | Handle @TestService.UnaryCall@
 --
 -- This is not implemented using the Protobuf communication patterns because
diff --git a/interop/Interop/Util/Messages.hs b/interop/Interop/Util/Messages.hs
index f38152cc..f410e1a3 100644
--- a/interop/Interop/Util/Messages.hs
+++ b/interop/Interop/Util/Messages.hs
@@ -12,9 +12,12 @@ import Data.ByteString qualified as BS.Strict
 import Data.ByteString qualified as Strict (ByteString)
 import Data.ByteString.Char8 qualified as BS.Strict.Char8
 
-import Interop.API
+import Network.GRPC.Common.Protobuf
+
 import Interop.Util.Exceptions
 
+import Proto.API.Interop
+
 {-------------------------------------------------------------------------------
   BoolValue
 -------------------------------------------------------------------------------}
diff --git a/demo-common/Demo/Common/API.hs b/proto/Proto/API/Helloworld.hs
similarity index 60%
rename from demo-common/Demo/Common/API.hs
rename to proto/Proto/API/Helloworld.hs
index d7de4aab..394b8ea8 100644
--- a/demo-common/Demo/Common/API.hs
+++ b/proto/Proto/API/Helloworld.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# OPTIONS_GHC -Wno-orphans #-}
 
-module Demo.Common.API (
+module Proto.API.Helloworld (
     -- * Greeter
     SayHello
   , SayHelloStreamReply
@@ -10,18 +10,8 @@ module Demo.Common.API (
     -- ** Metadata
   , SayHelloMetadata(..)
 
-    -- * RouteGuide
-  , GetFeature
-  , ListFeatures
-  , RecordRoute
-  , RouteChat
-
-    -- * Ping
-  , Ping
-
     -- * Re-exports
   , module Proto.Helloworld
-  , module Proto.RouteGuide
   ) where
 
 import Control.Monad.Catch
@@ -32,8 +22,6 @@ import Network.GRPC.Common
 import Network.GRPC.Common.Protobuf
 
 import Proto.Helloworld
-import Proto.RouteGuide
-import Network.GRPC.Common.Binary
 
 {-------------------------------------------------------------------------------
   Greeter
@@ -73,27 +61,4 @@ instance ParseMetadata SayHelloMetadata where
         [md] | customMetadataName md == "initial-md" ->
           return $ SayHelloMetadata $ Just (customMetadataValue md)
         _otherwise ->
-          throwM $ UnexpectedMetadata headers
-
-{-------------------------------------------------------------------------------
-  RouteGuide
--------------------------------------------------------------------------------}
-
-type GetFeature   = Protobuf RouteGuide "getFeature"
-type ListFeatures = Protobuf RouteGuide "listFeatures"
-type RecordRoute  = Protobuf RouteGuide "recordRoute"
-type RouteChat    = Protobuf RouteGuide "routeChat"
-
-type instance RequestMetadata          (Protobuf RouteGuide meth) = NoMetadata
-type instance ResponseInitialMetadata  (Protobuf RouteGuide meth) = NoMetadata
-type instance ResponseTrailingMetadata (Protobuf RouteGuide meth) = NoMetadata
-
-{-------------------------------------------------------------------------------
-  Ping
--------------------------------------------------------------------------------}
-
-type Ping = RawRpc "Ping" "ping"
-
-type instance RequestMetadata          (RawRpc "Ping" meth) = NoMetadata
-type instance ResponseInitialMetadata  (RawRpc "Ping" meth) = NoMetadata
-type instance ResponseTrailingMetadata (RawRpc "Ping" meth) = NoMetadata
+          throwM $ UnexpectedMetadata headers
\ No newline at end of file
diff --git a/interop/Interop/API.hs b/proto/Proto/API/Interop.hs
similarity index 91%
rename from interop/Interop/API.hs
rename to proto/Proto/API/Interop.hs
index 61d89a87..f4e30d81 100644
--- a/interop/Interop/API.hs
+++ b/proto/Proto/API/Interop.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# OPTIONS_GHC -Wno-orphans #-}
 
-module Interop.API (
+module Proto.API.Interop (
     -- * TestService
 
     -- ** Endpoints
@@ -20,14 +20,9 @@ module Interop.API (
     -- * UnimplementedService
   , UnimplementedServiceCall
 
-    -- * PingService
-  , Ping
-
     -- * Re-exports
-  , module Network.GRPC.Common.Protobuf
   , module Proto.Empty
   , module Proto.Messages
-  , module Proto.Ping
   , module Proto.Test
   ) where
 
@@ -40,7 +35,6 @@ import Network.GRPC.Common.Protobuf
 
 import Proto.Empty
 import Proto.Messages
-import Proto.Ping
 import Proto.Test
 
 {-------------------------------------------------------------------------------
@@ -183,13 +177,3 @@ type UnimplementedServiceCall = Protobuf UnimplementedService "unimplementedCall
 type instance RequestMetadata          (Protobuf UnimplementedService meth) = NoMetadata
 type instance ResponseInitialMetadata  (Protobuf UnimplementedService meth) = NoMetadata
 type instance ResponseTrailingMetadata (Protobuf UnimplementedService meth) = NoMetadata
-
-{-------------------------------------------------------------------------------
-  Ping service
--------------------------------------------------------------------------------}
-
-type Ping = Protobuf PingService "ping"
-
-type instance RequestMetadata          (Protobuf PingService meth) = NoMetadata
-type instance ResponseInitialMetadata  (Protobuf PingService meth) = NoMetadata
-type instance ResponseTrailingMetadata (Protobuf PingService meth) = NoMetadata
diff --git a/proto/Proto/API/Ping.hs b/proto/Proto/API/Ping.hs
new file mode 100644
index 00000000..ff06e955
--- /dev/null
+++ b/proto/Proto/API/Ping.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -Wno-orphans #-}
+
+module Proto.API.Ping (
+    Ping
+
+    -- * Re-exports
+  , module Proto.Ping
+) where
+
+import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
+
+import Proto.Ping
+
+{-------------------------------------------------------------------------------
+  Ping
+-------------------------------------------------------------------------------}
+
+type Ping = Protobuf PingService "ping"
+
+type instance RequestMetadata          (Protobuf PingService meth) = NoMetadata
+type instance ResponseInitialMetadata  (Protobuf PingService meth) = NoMetadata
+type instance ResponseTrailingMetadata (Protobuf PingService meth) = NoMetadata
diff --git a/proto/Proto/API/RouteGuide.hs b/proto/Proto/API/RouteGuide.hs
new file mode 100644
index 00000000..bed16497
--- /dev/null
+++ b/proto/Proto/API/RouteGuide.hs
@@ -0,0 +1,30 @@
+{-# OPTIONS_GHC -Wno-orphans #-}
+
+module Proto.API.RouteGuide (
+    -- * RouteGuide
+    GetFeature
+  , ListFeatures
+  , RecordRoute
+  , RouteChat
+
+    -- * Re-exports
+  , module Proto.RouteGuide
+  ) where
+
+import Network.GRPC.Common
+import Network.GRPC.Common.Protobuf
+
+import Proto.RouteGuide
+
+{-------------------------------------------------------------------------------
+  RouteGuide
+-------------------------------------------------------------------------------}
+
+type GetFeature   = Protobuf RouteGuide "getFeature"
+type ListFeatures = Protobuf RouteGuide "listFeatures"
+type RecordRoute  = Protobuf RouteGuide "recordRoute"
+type RouteChat    = Protobuf RouteGuide "routeChat"
+
+type instance RequestMetadata          (Protobuf RouteGuide meth) = NoMetadata
+type instance ResponseInitialMetadata  (Protobuf RouteGuide meth) = NoMetadata
+type instance ResponseTrailingMetadata (Protobuf RouteGuide meth) = NoMetadata
diff --git a/test-grapesy/Test/Sanity/Interop.hs b/test-grapesy/Test/Sanity/Interop.hs
index 4b0772bc..c94fe9d2 100644
--- a/test-grapesy/Test/Sanity/Interop.hs
+++ b/test-grapesy/Test/Sanity/Interop.hs
@@ -15,7 +15,7 @@ import Test.Tasty.HUnit
 
 import Network.GRPC.Client qualified as Client
 import Network.GRPC.Client.Binary qualified as Client.Binary
-import Network.GRPC.Client.StreamType.IO.Binary qualified as Client.Binary
+import Network.GRPC.Client.StreamType.IO qualified as Client
 import Network.GRPC.Common
 import Network.GRPC.Common.Protobuf
 import Network.GRPC.Common.StreamElem qualified as StreamElem
@@ -24,8 +24,8 @@ import Network.GRPC.Server.Binary qualified as Server.Binary
 import Network.GRPC.Server.StreamType qualified as Server
 import Network.GRPC.Spec
 
-import Proto.Messages
-import Proto.Test
+import Proto.API.Interop
+import Proto.API.Ping
 
 import Test.Driver.ClientServer
 
@@ -53,28 +53,28 @@ tests = testGroup "Test.Sanity.Interop" [
   even if the first failed with a gRPC exception
 -------------------------------------------------------------------------------}
 
-type Ping = RawRpc "test" "ping"
-
 test_callAfterException :: IO ()
 test_callAfterException =
     testClientServer $ ClientServerTest {
         config = def
       , client = simpleTestClient $ \conn -> do
-          resp1 <- ping conn 0
+          resp1 <- ping conn $ defMessage & #id .~ 0
           case resp1 of
             Left _  -> return ()
             Right _ -> assertFailure "Expected gRPC exception"
 
-          resp2 <- ping conn 1
+          resp2 <- ping conn $ defMessage & #id .~ 1
           case resp2 of
             Left  _ -> assertFailure "Expected pong"
-            Right i -> assertEqual "pong" i 1
+            Right i -> assertEqual "pong" i (defMessage & #id .~ 1)
       , server = [
             Server.someRpcHandler $
               Server.mkRpcHandler @Ping $ \call -> do
-                i :: Word <- Server.Binary.recvFinalInput call
-                if i > 0 then
-                  Server.Binary.sendFinalOutput call (i, NoMetadata)
+                pingMsg <- Server.recvFinalInput call
+                if pingMsg ^. #id > 0 then do
+                  let pongMsg :: Proto PongMessage
+                      pongMsg = defMessage & #id .~ (pingMsg ^. #id)
+                  Server.sendFinalOutput call (pongMsg, NoMetadata)
                 else
                   Server.sendGrpcException call $ GrpcException {
                       grpcError         = GrpcInvalidArgument
@@ -84,8 +84,11 @@ test_callAfterException =
           ]
       }
   where
-    ping :: Client.Connection -> Word -> IO (Either SomeException Word)
-    ping conn = try . Client.Binary.nonStreaming conn (Client.rpc @Ping)
+    ping ::
+         Client.Connection
+      -> Proto PingMessage
+      -> IO (Either SomeException (Proto PongMessage))
+    ping conn = try . Client.nonStreaming conn (Client.rpc @Ping)
 
 {-------------------------------------------------------------------------------
   @empty_unary@
@@ -93,8 +96,6 @@ test_callAfterException =
   <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#empty_unary>
 -------------------------------------------------------------------------------}
 
-type EmptyCall = Protobuf TestService "emptyCall"
-
 -- | Test that the empty message has an empty encoding
 --
 -- This test fails if we unconditionally compress (the /compressed/ form of the
@@ -133,8 +134,6 @@ test_emptyUnary =
   <https://github.com/grpc/grpc/blob/master/doc/interop-test-descriptions.md#server_compressed_streaming>
 -------------------------------------------------------------------------------}
 
-type StreamingOutputCall = Protobuf TestService "streamingOutputCall"
-
 -- | Test that we can enable and disable compression per message
 test_serverCompressedStreaming :: IO ()
 test_serverCompressedStreaming =
@@ -188,7 +187,7 @@ test_serverCompressedStreaming =
           Server.sendOutputWithEnvelope call $ StreamElem (envelope, response)
 
         -- No further output
-        Server.sendTrailers call NoMetadata
+        Server.sendTrailers call def
 
     verifyOutputs ::
          ( Maybe (InboundEnvelope, Proto StreamingOutputCallResponse)
@@ -278,10 +277,6 @@ test_cancellation_server =
   Internal: we don't care about metadata in these tests
 -------------------------------------------------------------------------------}
 
-type instance RequestMetadata          (Protobuf TestService meth) = NoMetadata
-type instance ResponseInitialMetadata  (Protobuf TestService meth) = NoMetadata
-type instance ResponseTrailingMetadata (Protobuf TestService meth) = NoMetadata
-
 type instance RequestMetadata          (RawRpc "test" meth) = NoMetadata
 type instance ResponseInitialMetadata  (RawRpc "test" meth) = NoMetadata
 type instance ResponseTrailingMetadata (RawRpc "test" meth) = NoMetadata