diff --git a/smithy4play/src/main/scala/de/innfactory/smithy4play/SmithyPlayEndpoint.scala b/smithy4play/src/main/scala/de/innfactory/smithy4play/SmithyPlayEndpoint.scala
index c1f82e1e..6a8faf1c 100644
--- a/smithy4play/src/main/scala/de/innfactory/smithy4play/SmithyPlayEndpoint.scala
+++ b/smithy4play/src/main/scala/de/innfactory/smithy4play/SmithyPlayEndpoint.scala
@@ -1,20 +1,20 @@
 package de.innfactory.smithy4play
 
 import akka.util.ByteString
-import cats.data.{EitherT, Kleisli}
+import cats.data.{ EitherT, Kleisli }
 import cats.implicits.toBifunctorOps
 import de.innfactory.smithy4play
 import de.innfactory.smithy4play.middleware.MiddlewareBase
 import play.api.mvc._
-import smithy4s.codecs.{PayloadError, StringAndBlobCodecs}
-import smithy4s.http.{HttpEndpoint, HttpResponse, Metadata, PathParams}
+import smithy4s.codecs.{ PayloadError, StringAndBlobCodecs }
+import smithy4s.http.{ HttpEndpoint, HttpResponse, Metadata, PathParams }
 import smithy4s.json.Json
 import smithy4s.kinds.FunctorInterpreter
-import smithy4s.schema.{CachedSchemaCompiler, Schema}
-import smithy4s.xml.{Xml, XmlDecodeError}
-import smithy4s.{Blob, Endpoint, Service}
+import smithy4s.schema.{ CachedSchemaCompiler, Schema }
+import smithy4s.xml.{ Xml, XmlDecodeError }
+import smithy4s.{ Blob, Endpoint, Service }
 
-import scala.concurrent.{ExecutionContext, Future}
+import scala.concurrent.{ ExecutionContext, Future }
 
 class SmithyPlayEndpoint[Alg[_[_, _, _, _, _]], F[_] <: ContextRoute[_], Op[
   _,
@@ -112,8 +112,8 @@ class SmithyPlayEndpoint[Alg[_[_, _, _, _, _]], F[_] <: ContextRoute[_], Op[
     EitherT(
       Future {
         val contentType = request.contentType.getOrElse("application/json")
-        val x = inputMetadataDecoder.decode(metadata)
-        val codecs = contentType match {
+        val x           = inputMetadataDecoder.decode(metadata)
+        val codecs      = contentType match {
           case "application/json" => (blob: Blob) => Json.read(blob)(inputSchema)
           case "application/xml"  => (blob: Blob) => Xml.read(blob)(inputSchema)
           case _                  =>
@@ -124,8 +124,8 @@ class SmithyPlayEndpoint[Alg[_[_, _, _, _, _]], F[_] <: ContextRoute[_], Op[
                 .decode(blob)
         }
         codecs(Blob(request.body.asBytes().getOrElse(ByteString.empty).toByteBuffer)).leftMap {
-          case error: PayloadError   => Smithy4PlayError(error.expected, smithy4play.Status(Map.empty, 400))
-          case error: XmlDecodeError => Smithy4PlayError(error.getMessage(), smithy4play.Status(Map.empty, 400))
+          case error: PayloadError   => Smithy4PlayError(error.expected, smithy4play.Status(Map.empty, 500))
+          case error: XmlDecodeError => Smithy4PlayError(error.getMessage(), smithy4play.Status(Map.empty, 500))
         }
       }
     )
diff --git a/smithy4play/src/main/scala/de/innfactory/smithy4play/client/SmithyPlayClientEndpoint.scala b/smithy4play/src/main/scala/de/innfactory/smithy4play/client/SmithyPlayClientEndpoint.scala
index c5704b1e..04e8dd48 100644
--- a/smithy4play/src/main/scala/de/innfactory/smithy4play/client/SmithyPlayClientEndpoint.scala
+++ b/smithy4play/src/main/scala/de/innfactory/smithy4play/client/SmithyPlayClientEndpoint.scala
@@ -2,13 +2,16 @@ package de.innfactory
 package smithy4play
 package client
 import cats.implicits._
-import smithy4s.codecs.{ PayloadError, StringAndBlobCodecs }
-import smithy4s.http.{ CaseInsensitive, HttpEndpoint, Metadata, MetadataError }
+import smithy4s.codecs.{PayloadError, StringAndBlobCodecs}
+import smithy4s.http.{CaseInsensitive, HttpEndpoint, Metadata, MetadataError}
 import smithy4s.json.Json
-import smithy4s.xml.{ Xml, XmlDecodeError }
-import smithy4s.{ Blob, Endpoint, Schema }
+import smithy4s.json.Json.payloadCodecs
+import smithy4s.schema.CachedSchemaCompiler
+import smithy4s.xml.internals.XmlEncoder
+import smithy4s.xml.{Xml, XmlDecodeError, XmlDocument}
+import smithy4s.{Blob, Endpoint, Schema}
 
-import scala.concurrent.{ ExecutionContext, Future }
+import scala.concurrent.{ExecutionContext, Future}
 
 private[smithy4play] class SmithyPlayClientEndpoint[Op[_, _, _, _, _], I, E, O, SI, SO](
   endpoint: Endpoint[Op, I, E, O, SI, SO],
@@ -33,12 +36,35 @@ private[smithy4play] class SmithyPlayClientEndpoint[Op[_, _, _, _, _], I, E, O,
     val metadata        = inputMetadataEncoder.encode(input)
     val path            = buildPath(metadata)
     val headers         = metadata.headers.map(x => (x._1.toString.toLowerCase, x._2))
+    val contentType     = headers.getOrElse("content-type", Seq("application/json"))
     val headersWithAuth = if (additionalHeaders.isDefined) headers.combine(additionalHeaders.get) else headers
     val code            = httpEndpoint.code
-    val response        = client.send(httpEndpoint.method.toString, path, headersWithAuth, Json.writeBlob(input))
+    val response        =
+      client.send(
+        httpEndpoint.method.toString,
+        path,
+        headersWithAuth.combine(Map("content-type" -> contentType)),
+        writeInputToBlob(input, contentType)
+      )
     decodeResponse(response, code)
   }
 
+  private def writeInputToBlob(input: I, contentType: Seq[String]): Blob = {
+    //TODO: Use Correct Encoders for Json and Xml and fix StringAndBlobCodecs
+    contentType match {
+      case Seq("application/json") =>  Json.writeBlob(input)
+      case Seq("application/xml")  => Xml.write(input)
+      case _                       =>
+        StringAndBlobCodecs.encoders
+          .fromSchema(inputSchema)
+          .map(_.encode(input))
+          .getOrElse({
+            logger.info("sending empty blob")
+            Blob.empty
+          })
+    }
+  }
+
   private def decodeResponse(
     response: Future[SmithyClientResponse],
     expectedCode: Int