diff --git a/client/client.go b/client/client.go
index 74ec51be..32cb9a6b 100644
--- a/client/client.go
+++ b/client/client.go
@@ -4,6 +4,8 @@ package client
 import (
 	"context"
 	"time"
+
+	"github.com/micro/go-micro/codec"
 )
 
 // Client is the interface used to make requests to services.
@@ -20,6 +22,11 @@ type Client interface {
 	String() string
 }
 
+// Router manages request routing
+type Router interface {
+	SendRequest(context.Context, Request) (Response, error)
+}
+
 // Message is the interface for publishing asynchronously
 type Message interface {
 	Topic() string
@@ -29,14 +36,30 @@ type Message interface {
 
 // Request is the interface for a synchronous request used by Call or Stream
 type Request interface {
+	// The service to call
 	Service() string
+	// The method to call
 	Method() string
+	// The content type
 	ContentType() string
-	Request() interface{}
+	// The unencoded request body
+	Body() interface{}
+	// Write to the encoded request writer. This is nil before a call is made
+	Codec() codec.Writer
 	// indicates whether the request will be a streaming one rather than unary
 	Stream() bool
 }
 
+// Response is the response received from a service
+type Response interface {
+	// Read the response
+	Codec() codec.Reader
+	// read the header
+	Header() map[string]string
+	// Read the undecoded response
+	Read() ([]byte, error)
+}
+
 // Stream is the inteface for a bidirectional synchronous stream
 type Stream interface {
 	Context() context.Context
diff --git a/client/rpc_client.go b/client/rpc_client.go
index 04be269e..336dd34f 100644
--- a/client/rpc_client.go
+++ b/client/rpc_client.go
@@ -97,7 +97,7 @@ func (r *rpcClient) call(ctx context.Context, address string, req Request, resp
 		request: req,
 		closed:  make(chan bool),
 		codec:   newRpcCodec(msg, c, cf),
-		seq:     fmt.Sprintf("%v", seq),
+		id:      fmt.Sprintf("%v", seq),
 	}
 	defer stream.Close()
 
@@ -111,7 +111,7 @@ func (r *rpcClient) call(ctx context.Context, address string, req Request, resp
 		}()
 
 		// send request
-		if err := stream.Send(req.Request()); err != nil {
+		if err := stream.Send(req.Body()); err != nil {
 			ch <- err
 			return
 		}
@@ -183,7 +183,7 @@ func (r *rpcClient) stream(ctx context.Context, address string, req Request, opt
 	ch := make(chan error, 1)
 
 	go func() {
-		ch <- stream.Send(req.Request())
+		ch <- stream.Send(req.Body())
 	}()
 
 	var grr error
diff --git a/client/rpc_codec.go b/client/rpc_codec.go
index d269392f..fe694380 100644
--- a/client/rpc_codec.go
+++ b/client/rpc_codec.go
@@ -3,7 +3,6 @@ package client
 import (
 	"bytes"
 	errs "errors"
-	"fmt"
 
 	"github.com/micro/go-micro/codec"
 	raw "github.com/micro/go-micro/codec/bytes"
@@ -85,7 +84,7 @@ func (rwc *readWriteCloser) Close() error {
 	return nil
 }
 
-func newRpcCodec(req *transport.Message, client transport.Client, c codec.NewCodec) *rpcCodec {
+func newRpcCodec(req *transport.Message, client transport.Client, c codec.NewCodec) codec.Codec {
 	rwc := &readWriteCloser{
 		wbuf: bytes.NewBuffer(nil),
 		rbuf: bytes.NewBuffer(nil),
@@ -99,34 +98,45 @@ func newRpcCodec(req *transport.Message, client transport.Client, c codec.NewCod
 	return r
 }
 
-func (c *rpcCodec) Write(req *request, body interface{}) error {
+func (c *rpcCodec) Write(wm *codec.Message, body interface{}) error {
 	c.buf.wbuf.Reset()
 
 	m := &codec.Message{
-		Id:     req.Seq,
-		Target: req.Service,
-		Method: req.ServiceMethod,
+		Id:     wm.Id,
+		Target: wm.Target,
+		Method: wm.Method,
 		Type:   codec.Request,
 		Header: map[string]string{
-			"X-Micro-Id":      fmt.Sprintf("%v", req.Seq),
-			"X-Micro-Service": req.Service,
-			"X-Micro-Method":  req.ServiceMethod,
+			"X-Micro-Id":      wm.Id,
+			"X-Micro-Service": wm.Target,
+			"X-Micro-Method":  wm.Method,
 		},
 	}
+
 	if err := c.codec.Write(m, body); err != nil {
 		return errors.InternalServerError("go.micro.client.codec", err.Error())
 	}
-	c.req.Body = c.buf.wbuf.Bytes()
+
+	// set body
+	if len(wm.Body) > 0 {
+		c.req.Body = wm.Body
+	} else {
+		c.req.Body = c.buf.wbuf.Bytes()
+	}
+
+	// set header
 	for k, v := range m.Header {
 		c.req.Header[k] = v
 	}
+
+	// send the request
 	if err := c.client.Send(c.req); err != nil {
 		return errors.InternalServerError("go.micro.client.transport", err.Error())
 	}
 	return nil
 }
 
-func (c *rpcCodec) Read(r *response, b interface{}) error {
+func (c *rpcCodec) ReadHeader(wm *codec.Message, r codec.MessageType) error {
 	var m transport.Message
 	if err := c.client.Recv(&m); err != nil {
 		return errors.InternalServerError("go.micro.client.transport", err.Error())
@@ -139,34 +149,38 @@ func (c *rpcCodec) Read(r *response, b interface{}) error {
 	me.Header = m.Header
 
 	// read header
-	err := c.codec.ReadHeader(&me, codec.Response)
-	r.ServiceMethod = me.Method
-	r.Seq = me.Id
-	r.Error = me.Error
+	err := c.codec.ReadHeader(&me, r)
+	wm.Method = me.Method
+	wm.Id = me.Id
+	wm.Error = me.Error
 
 	// check error in header
 	if len(me.Error) == 0 {
-		r.Error = me.Header["X-Micro-Error"]
+		wm.Error = me.Header["X-Micro-Error"]
 	}
 
 	// check method in header
 	if len(me.Method) == 0 {
-		r.ServiceMethod = me.Header["X-Micro-Method"]
+		wm.Method = me.Header["X-Micro-Method"]
 	}
 
 	if len(me.Id) == 0 {
-		r.Seq = me.Header["X-Micro-Id"]
+		wm.Id = me.Header["X-Micro-Id"]
 	}
 
+	// return header error
 	if err != nil {
 		return errors.InternalServerError("go.micro.client.codec", err.Error())
 	}
 
+	return nil
+}
+
+func (c *rpcCodec) ReadBody(b interface{}) error {
 	// read body
 	if err := c.codec.ReadBody(b); err != nil {
 		return errors.InternalServerError("go.micro.client.codec", err.Error())
 	}
-
 	return nil
 }
 
@@ -178,3 +192,7 @@ func (c *rpcCodec) Close() error {
 	}
 	return nil
 }
+
+func (c *rpcCodec) String() string {
+	return "rpc"
+}
diff --git a/client/rpc_request.go b/client/rpc_request.go
index 04ce490a..b7f9695e 100644
--- a/client/rpc_request.go
+++ b/client/rpc_request.go
@@ -1,10 +1,15 @@
 package client
 
+import (
+	"github.com/micro/go-micro/codec"
+)
+
 type rpcRequest struct {
 	service     string
 	method      string
 	contentType string
-	request     interface{}
+	codec       codec.Codec
+	body        interface{}
 	opts        RequestOptions
 }
 
@@ -23,7 +28,7 @@ func newRequest(service, method string, request interface{}, contentType string,
 	return &rpcRequest{
 		service:     service,
 		method:      method,
-		request:     request,
+		body:        request,
 		contentType: contentType,
 		opts:        opts,
 	}
@@ -41,8 +46,12 @@ func (r *rpcRequest) Method() string {
 	return r.method
 }
 
-func (r *rpcRequest) Request() interface{} {
-	return r.request
+func (r *rpcRequest) Body() interface{} {
+	return r.body
+}
+
+func (r *rpcRequest) Codec() codec.Writer {
+	return r.codec
 }
 
 func (r *rpcRequest) Stream() bool {
diff --git a/client/rpc_stream.go b/client/rpc_stream.go
index 334b1fc0..838172d4 100644
--- a/client/rpc_stream.go
+++ b/client/rpc_stream.go
@@ -4,16 +4,18 @@ import (
 	"context"
 	"io"
 	"sync"
+
+	"github.com/micro/go-micro/codec"
 )
 
 // Implements the streamer interface
 type rpcStream struct {
 	sync.RWMutex
-	seq     string
+	id      string
 	closed  chan bool
 	err     error
 	request Request
-	codec   *rpcCodec
+	codec   codec.Codec
 	context context.Context
 }
 
@@ -43,18 +45,18 @@ func (r *rpcStream) Send(msg interface{}) error {
 		return errShutdown
 	}
 
-	seq := r.seq
-
-	req := request{
-		Service:       r.request.Service(),
-		Seq:           seq,
-		ServiceMethod: r.request.Method(),
+	req := codec.Message{
+		Id:     r.id,
+		Target: r.request.Service(),
+		Method: r.request.Method(),
+		Type:   codec.Request,
 	}
 
 	if err := r.codec.Write(&req, msg); err != nil {
 		r.err = err
 		return err
 	}
+
 	return nil
 }
 
@@ -67,9 +69,9 @@ func (r *rpcStream) Recv(msg interface{}) error {
 		return errShutdown
 	}
 
-	var resp response
+	var resp codec.Message
 
-	if err := r.codec.Read(&resp, msg); err != nil {
+	if err := r.codec.ReadHeader(&resp, codec.Response); err != nil {
 		if err == io.EOF && !r.isClosed() {
 			r.err = io.ErrUnexpectedEOF
 			return io.ErrUnexpectedEOF
@@ -81,13 +83,20 @@ func (r *rpcStream) Recv(msg interface{}) error {
 	switch {
 	case len(resp.Error) > 0:
 		// We've got an error response. Give this to the request;
-		// any subsequent requests will get the ReadBody
+		// any subsequent requests will get the ReadResponseBody
 		// error if there is one.
 		if resp.Error != lastStreamResponseError {
 			r.err = serverError(resp.Error)
 		} else {
 			r.err = io.EOF
 		}
+		if err := r.codec.ReadBody(nil); err != nil {
+			r.err = err
+		}
+	default:
+		if err := r.codec.ReadBody(msg); err != nil {
+			r.err = err
+		}
 	}
 
 	return r.err