diff --git a/clientapi/routing/joinroom.go b/clientapi/routing/joinroom.go
index f72bb9162..d0dee7c2a 100644
--- a/clientapi/routing/joinroom.go
+++ b/clientapi/routing/joinroom.go
@@ -386,7 +386,7 @@ func (r joinRoomReq) joinRoomUsingServer(roomID string, server gomatrixserverlib
 
 	if err = r.producer.SendEventWithState(
 		r.req.Context(),
-		gomatrixserverlib.RespState(respSendJoin.RespState),
+		respSendJoin.ToRespState(),
 		event.Headered(respMakeJoin.RoomVersion),
 	); err != nil {
 		util.GetLogger(r.req.Context()).WithError(err).Error("r.producer.SendEventWithState")
diff --git a/federationapi/routing/join.go b/federationapi/routing/join.go
index e06785954..0c899ab9f 100644
--- a/federationapi/routing/join.go
+++ b/federationapi/routing/join.go
@@ -252,9 +252,12 @@ func SendJoin(
 
 	return util.JSONResponse{
 		Code: http.StatusOK,
-		JSON: map[string]interface{}{
-			"state":      gomatrixserverlib.UnwrapEventHeaders(stateAndAuthChainResponse.StateEvents),
-			"auth_chain": gomatrixserverlib.UnwrapEventHeaders(stateAndAuthChainResponse.AuthChainEvents),
+		JSON: gomatrixserverlib.RespSendJoin{
+			RespState: gomatrixserverlib.RespState{
+				StateEvents: gomatrixserverlib.UnwrapEventHeaders(stateAndAuthChainResponse.StateEvents),
+				AuthEvents:  gomatrixserverlib.UnwrapEventHeaders(stateAndAuthChainResponse.AuthChainEvents),
+			},
+			Origin: cfg.Matrix.ServerName,
 		},
 	}
 }