diff --git a/chats/handler/chats.go b/chats/handler/chats.go
index 6ef3149..72483d9 100644
--- a/chats/handler/chats.go
+++ b/chats/handler/chats.go
@@ -40,13 +40,25 @@ type Message struct {
 	SentAt   time.Time
 }
 
+func ParseTime(v string) time.Time {
+	t, err := time.Parse(time.RFC3339Nano, v)
+	if err == nil {
+		return t
+	}
+	t, err = time.Parse(time.RFC3339, v)
+	if err == nil {
+		return t
+	}
+	return time.Time{}
+}
+
 func (m *Message) Serialize() *pb.Message {
 	return &pb.Message{
 		Id:       m.ID,
 		AuthorId: m.AuthorID,
 		ChatId:   m.ChatID,
 		Text:     m.Text,
-		SentAt:   m.SentAt.UnixNano(),
+		SentAt:   m.SentAt.Format(time.RFC3339Nano),
 	}
 }
 
@@ -109,6 +121,6 @@ func (c *Chat) Serialize() *pb.Chat {
 	return &pb.Chat{
 		Id:        c.ID,
 		UserIds:   c.UserIDs,
-		CreatedAt: c.CreatedAt.UnixNano(),
+		CreatedAt: c.CreatedAt.Format(time.RFC3339Nano),
 	}
 }
diff --git a/chats/handler/chats_test.go b/chats/handler/chats_test.go
index ea83c3a..67d8274 100644
--- a/chats/handler/chats_test.go
+++ b/chats/handler/chats_test.go
@@ -34,7 +34,7 @@ func assertChatsMatch(t *testing.T, exp, act *pb.Chat) {
 
 	assert.Equal(t, exp.UserIds, act.UserIds)
 
-	if act.CreatedAt == 0 {
+	if len(act.CreatedAt) == 0 {
 		t.Errorf("CreatedAt not set")
 		return
 	}
@@ -59,7 +59,7 @@ func assertMessagesMatch(t *testing.T, exp, act *pb.Message) {
 	assert.Equal(t, exp.AuthorId, act.AuthorId)
 	assert.Equal(t, exp.ChatId, act.ChatId)
 
-	if act.SentAt == 0 {
+	if len(act.SentAt) == 0 {
 		t.Errorf("SentAt not set")
 		return
 	}
diff --git a/chats/handler/create_message_test.go b/chats/handler/create_message_test.go
index 0bd1f42..9d4c942 100644
--- a/chats/handler/create_message_test.go
+++ b/chats/handler/create_message_test.go
@@ -2,6 +2,7 @@ package handler_test
 
 import (
 	"testing"
+	"time"
 
 	"github.com/micro/services/chats/handler"
 	pb "github.com/micro/services/chats/proto"
@@ -98,7 +99,7 @@ func TestSendMessage(t *testing.T) {
 			assertMessagesMatch(t, &pb.Message{
 				AuthorId: tc.AuthorID,
 				ChatId:   tc.ChatID,
-				SentAt:   h.Time().UnixNano(),
+				SentAt:   h.Time().Format(time.RFC3339Nano),
 				Text:     tc.Text,
 				Id:       tc.ID,
 			}, rsp.Message)
diff --git a/chats/handler/list_messages_test.go b/chats/handler/list_messages_test.go
index 0a5e3be..b7b1347 100644
--- a/chats/handler/list_messages_test.go
+++ b/chats/handler/list_messages_test.go
@@ -106,9 +106,9 @@ func TestListMessages(t *testing.T) {
 // sortMessages by the time they were sent
 func sortMessages(msgs []*pb.Message) {
 	sort.Slice(msgs, func(i, j int) bool {
-		if msgs[i].SentAt == 0 || msgs[j].SentAt == 0 {
+		if len(msgs[i].SentAt) == 0 || len(msgs[j].SentAt) == 0 {
 			return true
 		}
-		return msgs[i].SentAt < msgs[j].SentAt
+		return handler.ParseTime(msgs[i].SentAt).Before(handler.ParseTime(msgs[j].SentAt))
 	})
 }
diff --git a/chats/proto/chats.pb.go b/chats/proto/chats.pb.go
index e910e30..273a36f 100644
--- a/chats/proto/chats.pb.go
+++ b/chats/proto/chats.pb.go
@@ -29,8 +29,8 @@ type Chat struct {
 	Id string `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
 	// list of users in the chat
 	UserIds []string `protobuf:"bytes,2,rep,name=user_ids,json=userIds,proto3" json:"user_ids,omitempty"`
-	// unix nanosecond timestamp
-	CreatedAt int64 `protobuf:"varint,3,opt,name=created_at,json=createdAt,proto3" json:"created_at,omitempty"`
+	// RFC3339Nano timestamp
+	CreatedAt string `protobuf:"bytes,3,opt,name=created_at,json=createdAt,proto3" json:"created_at,omitempty"`
 }
 
 func (x *Chat) Reset() {
@@ -79,11 +79,11 @@ func (x *Chat) GetUserIds() []string {
 	return nil
 }
 
-func (x *Chat) GetCreatedAt() int64 {
+func (x *Chat) GetCreatedAt() string {
 	if x != nil {
 		return x.CreatedAt
 	}
-	return 0
+	return ""
 }
 
 type Message struct {
@@ -99,8 +99,8 @@ type Message struct {
 	ChatId string `protobuf:"bytes,3,opt,name=chat_id,json=chatId,proto3" json:"chat_id,omitempty"`
 	// text within the message
 	Text string `protobuf:"bytes,4,opt,name=text,proto3" json:"text,omitempty"`
-	// unix nanosecond timestamp
-	SentAt int64 `protobuf:"varint,5,opt,name=sent_at,json=sentAt,proto3" json:"sent_at,omitempty"`
+	// RFC3339Nano timestamp
+	SentAt string `protobuf:"bytes,5,opt,name=sent_at,json=sentAt,proto3" json:"sent_at,omitempty"`
 }
 
 func (x *Message) Reset() {
@@ -163,11 +163,11 @@ func (x *Message) GetText() string {
 	return ""
 }
 
-func (x *Message) GetSentAt() int64 {
+func (x *Message) GetSentAt() string {
 	if x != nil {
 		return x.SentAt
 	}
-	return 0
+	return ""
 }
 
 // Create a new chat between mulitple users
@@ -526,7 +526,7 @@ var file_proto_chats_proto_rawDesc = []byte{
 	0x69, 0x64, 0x12, 0x19, 0x0a, 0x08, 0x75, 0x73, 0x65, 0x72, 0x5f, 0x69, 0x64, 0x73, 0x18, 0x02,
 	0x20, 0x03, 0x28, 0x09, 0x52, 0x07, 0x75, 0x73, 0x65, 0x72, 0x49, 0x64, 0x73, 0x12, 0x1d, 0x0a,
 	0x0a, 0x63, 0x72, 0x65, 0x61, 0x74, 0x65, 0x64, 0x5f, 0x61, 0x74, 0x18, 0x03, 0x20, 0x01, 0x28,
-	0x03, 0x52, 0x09, 0x63, 0x72, 0x65, 0x61, 0x74, 0x65, 0x64, 0x41, 0x74, 0x22, 0x7c, 0x0a, 0x07,
+	0x09, 0x52, 0x09, 0x63, 0x72, 0x65, 0x61, 0x74, 0x65, 0x64, 0x41, 0x74, 0x22, 0x7c, 0x0a, 0x07,
 	0x4d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65, 0x12, 0x0e, 0x0a, 0x02, 0x69, 0x64, 0x18, 0x01, 0x20,
 	0x01, 0x28, 0x09, 0x52, 0x02, 0x69, 0x64, 0x12, 0x1b, 0x0a, 0x09, 0x61, 0x75, 0x74, 0x68, 0x6f,
 	0x72, 0x5f, 0x69, 0x64, 0x18, 0x02, 0x20, 0x01, 0x28, 0x09, 0x52, 0x08, 0x61, 0x75, 0x74, 0x68,
@@ -534,7 +534,7 @@ var file_proto_chats_proto_rawDesc = []byte{
 	0x03, 0x20, 0x01, 0x28, 0x09, 0x52, 0x06, 0x63, 0x68, 0x61, 0x74, 0x49, 0x64, 0x12, 0x12, 0x0a,
 	0x04, 0x74, 0x65, 0x78, 0x74, 0x18, 0x04, 0x20, 0x01, 0x28, 0x09, 0x52, 0x04, 0x74, 0x65, 0x78,
 	0x74, 0x12, 0x17, 0x0a, 0x07, 0x73, 0x65, 0x6e, 0x74, 0x5f, 0x61, 0x74, 0x18, 0x05, 0x20, 0x01,
-	0x28, 0x03, 0x52, 0x06, 0x73, 0x65, 0x6e, 0x74, 0x41, 0x74, 0x22, 0x3e, 0x0a, 0x11, 0x43, 0x72,
+	0x28, 0x09, 0x52, 0x06, 0x73, 0x65, 0x6e, 0x74, 0x41, 0x74, 0x22, 0x3e, 0x0a, 0x11, 0x43, 0x72,
 	0x65, 0x61, 0x74, 0x65, 0x43, 0x68, 0x61, 0x74, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12,
 	0x0e, 0x0a, 0x02, 0x69, 0x64, 0x18, 0x01, 0x20, 0x01, 0x28, 0x09, 0x52, 0x02, 0x69, 0x64, 0x12,
 	0x19, 0x0a, 0x08, 0x75, 0x73, 0x65, 0x72, 0x5f, 0x69, 0x64, 0x73, 0x18, 0x02, 0x20, 0x03, 0x28,
diff --git a/chats/proto/chats.proto b/chats/proto/chats.proto
index 3d24ca0..e118018 100644
--- a/chats/proto/chats.proto
+++ b/chats/proto/chats.proto
@@ -20,8 +20,8 @@ message Chat {
 	string id = 1;
 	// list of users in the chat
 	repeated string user_ids = 2;
-	// unix nanosecond timestamp
-	int64 created_at = 3;
+	// RFC3339Nano timestamp
+	string created_at = 3;
 }
 
 message Message {
@@ -33,8 +33,8 @@ message Message {
 	string chat_id = 3;
 	// text within the message
 	string text = 4;
-	// unix nanosecond timestamp
-	int64 sent_at = 5;
+	// RFC3339Nano timestamp
+	string sent_at = 5;
 }
 
 // Create a new chat between mulitple users