diff --git a/go.mod b/go.mod
index d7d1a6b..4b9a42c 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ require (
 	github.com/golang/protobuf v1.4.3
 	github.com/google/go-cmp v0.5.1 // indirect
 	github.com/unistack-org/micro-codec-bytes v0.0.0-20200828083432-4e49e953d844
-	github.com/unistack-org/micro/v3 v3.0.0-gamma.0.20201104214903-1fbf8b2e209e
+	github.com/unistack-org/micro/v3 v3.0.2-0.20201117210202-01e64cb0c0f3
 	golang.org/x/net v0.0.0-20200904194848-62affa334b73
 	golang.org/x/sys v0.0.0-20200803210538-64077c9b5642 // indirect
 	golang.org/x/text v0.3.3 // indirect
diff --git a/go.sum b/go.sum
index 1b9bc29..08b8ae4 100644
--- a/go.sum
+++ b/go.sum
@@ -283,6 +283,10 @@ github.com/unistack-org/micro/v3 v3.0.0-gamma.0.20200920135754-1cbd1d2bad83/go.m
 github.com/unistack-org/micro/v3 v3.0.0-gamma.0.20200922103357-4c4fa00a5d94/go.mod h1:aL+8VhSXpx0SuEeXPOWUo5BgS7kyvWYobeXFay90UUM=
 github.com/unistack-org/micro/v3 v3.0.0-gamma.0.20201104214903-1fbf8b2e209e h1:v27OUgoE2UOyCe6uLksdpG6oErx62nUXWIkTPxS7yIw=
 github.com/unistack-org/micro/v3 v3.0.0-gamma.0.20201104214903-1fbf8b2e209e/go.mod h1:LFvCXGOgcLIj2k/8eL71TpIpcJBN2SXXAUx8U6dz9Rw=
+github.com/unistack-org/micro/v3 v3.0.2-0.20201114215340-e0ef8b2953b5 h1:iSyQgm4zZb8N/jphp5NOf6bC8FrGRcKNyDDtAeP1m5w=
+github.com/unistack-org/micro/v3 v3.0.2-0.20201114215340-e0ef8b2953b5/go.mod h1:LYbzHigEudM10AbLZztVSX0Y4JWgj5nKIExil/99h6E=
+github.com/unistack-org/micro/v3 v3.0.2-0.20201117210202-01e64cb0c0f3 h1:knz0mt3Ot/CIXp5dRyb5dAPYtKiWA9PDhazpXX5Iu3o=
+github.com/unistack-org/micro/v3 v3.0.2-0.20201117210202-01e64cb0c0f3/go.mod h1:LYbzHigEudM10AbLZztVSX0Y4JWgj5nKIExil/99h6E=
 github.com/urfave/cli v1.22.1/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
 github.com/vultr/govultr v0.1.4/go.mod h1:9H008Uxr/C4vFNGLqKx232C206GL0PBHzOP0809bGNA=
 github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f/go.mod h1:N2zxlSyiKSe5eX1tZViRH5QA0qijqEDrYZiPEAiq3wU=
diff --git a/request.go b/request.go
index 76f964d..893c9f8 100644
--- a/request.go
+++ b/request.go
@@ -3,6 +3,7 @@ package grpc
 import (
 	raw "github.com/unistack-org/micro-codec-bytes"
 	"github.com/unistack-org/micro/v3/codec"
+	"github.com/unistack-org/micro/v3/metadata"
 )
 
 type rpcRequest struct {
@@ -10,7 +11,7 @@ type rpcRequest struct {
 	method      string
 	contentType string
 	codec       codec.Codec
-	header      map[string]string
+	header      metadata.Metadata
 	body        []byte
 	stream      bool
 	payload     interface{}
@@ -20,7 +21,7 @@ type rpcMessage struct {
 	topic       string
 	contentType string
 	payload     interface{}
-	header      map[string]string
+	header      metadata.Metadata
 	body        []byte
 	codec       codec.Codec
 }
@@ -45,7 +46,7 @@ func (r *rpcRequest) Codec() codec.Reader {
 	return r.codec
 }
 
-func (r *rpcRequest) Header() map[string]string {
+func (r *rpcRequest) Header() metadata.Metadata {
 	return r.header
 }
 
@@ -77,7 +78,7 @@ func (r *rpcMessage) Payload() interface{} {
 	return r.payload
 }
 
-func (r *rpcMessage) Header() map[string]string {
+func (r *rpcMessage) Header() metadata.Metadata {
 	return r.header
 }
 
diff --git a/response.go b/response.go
index fff96a9..a6a52a2 100644
--- a/response.go
+++ b/response.go
@@ -2,10 +2,11 @@ package grpc
 
 import (
 	"github.com/unistack-org/micro/v3/codec"
+	"github.com/unistack-org/micro/v3/metadata"
 )
 
 type rpcResponse struct {
-	header map[string]string
+	header metadata.Metadata
 	codec  codec.Codec
 }
 
@@ -13,7 +14,7 @@ func (r *rpcResponse) Codec() codec.Writer {
 	return r.codec
 }
 
-func (r *rpcResponse) WriteHeader(hdr map[string]string) {
+func (r *rpcResponse) WriteHeader(hdr metadata.Metadata) {
 	for k, v := range hdr {
 		r.header[k] = v
 	}