diff --git a/cartographer_grpc/mapping/map_builder_stub.cc b/cartographer_grpc/client/map_builder_stub.cc
similarity index 93%
rename from cartographer_grpc/mapping/map_builder_stub.cc
rename to cartographer_grpc/client/map_builder_stub.cc
index 5fe43c1..a85cbb1 100644
--- a/cartographer_grpc/mapping/map_builder_stub.cc
+++ b/cartographer_grpc/client/map_builder_stub.cc
@@ -14,23 +14,31 @@
  * limitations under the License.
  */
 
-#include "cartographer_grpc/mapping/map_builder_stub.h"
+#include "cartographer_grpc/client/map_builder_stub.h"
+
 #include "cartographer_grpc/handlers/add_trajectory_handler.h"
 #include "cartographer_grpc/handlers/finish_trajectory_handler.h"
 #include "cartographer_grpc/handlers/get_submap_handler.h"
 #include "cartographer_grpc/handlers/load_state_handler.h"
 #include "cartographer_grpc/handlers/write_state_handler.h"
+#include "cartographer_grpc/internal/client/pose_graph_stub.h"
+#include "cartographer_grpc/internal/client/trajectory_builder_stub.h"
 #include "cartographer_grpc/proto/map_builder_service.pb.h"
 #include "cartographer_grpc/sensor/serialization.h"
 #include "glog/logging.h"
 
 namespace cartographer_grpc {
 namespace mapping {
+namespace {
+
+using ::cartographer::common::make_unique;
+
+}  // namespace
 
 MapBuilderStub::MapBuilderStub(const std::string& server_address)
     : client_channel_(grpc::CreateChannel(server_address,
                                           grpc::InsecureChannelCredentials())),
-      pose_graph_stub_(client_channel_) {}
+      pose_graph_stub_(make_unique<PoseGraphStub>(client_channel_)) {}
 
 int MapBuilderStub::AddTrajectoryBuilder(
     const std::set<SensorId>& expected_sensor_ids,
@@ -52,8 +60,7 @@ int MapBuilderStub::AddTrajectoryBuilder(
   trajectory_builder_stubs_.emplace(
       std::piecewise_construct,
       std::forward_as_tuple(client.response().trajectory_id()),
-      std::forward_as_tuple(cartographer::common::make_unique<
-                            cartographer_grpc::mapping::TrajectoryBuilderStub>(
+      std::forward_as_tuple(make_unique<TrajectoryBuilderStub>(
           client_channel_, client.response().trajectory_id(),
           local_slam_result_callback)));
   return client.response().trajectory_id();
@@ -150,7 +157,7 @@ int MapBuilderStub::num_trajectory_builders() const {
 }
 
 cartographer::mapping::PoseGraphInterface* MapBuilderStub::pose_graph() {
-  return &pose_graph_stub_;
+  return pose_graph_stub_.get();
 }
 
 const std::vector<
diff --git a/cartographer_grpc/mapping/map_builder_stub.h b/cartographer_grpc/client/map_builder_stub.h
similarity index 84%
rename from cartographer_grpc/mapping/map_builder_stub.h
rename to cartographer_grpc/client/map_builder_stub.h
index 2c226b4..c8c6458 100644
--- a/cartographer_grpc/mapping/map_builder_stub.h
+++ b/cartographer_grpc/client/map_builder_stub.h
@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_GRPC_MAPPING_MAP_BUILDER_STUB_H_
-#define CARTOGRAPHER_GRPC_MAPPING_MAP_BUILDER_STUB_H_
+#ifndef CARTOGRAPHER_GRPC_CLIENT_MAP_BUILDER_STUB_H_
+#define CARTOGRAPHER_GRPC_CLIENT_MAP_BUILDER_STUB_H_
 
 #include <memory>
 
 #include "cartographer/mapping/map_builder_interface.h"
-#include "cartographer_grpc/mapping/pose_graph_stub.h"
-#include "cartographer_grpc/mapping/trajectory_builder_stub.h"
+#include "cartographer/mapping/pose_graph_interface.h"
+#include "cartographer/mapping/trajectory_builder_interface.h"
 #include "grpc++/grpc++.h"
 
 namespace cartographer_grpc {
@@ -60,12 +60,13 @@ class MapBuilderStub : public cartographer::mapping::MapBuilderInterface {
 
  private:
   std::shared_ptr<grpc::Channel> client_channel_;
-  PoseGraphStub pose_graph_stub_;
-  std::map<int, std::unique_ptr<TrajectoryBuilderStub>>
+  std::unique_ptr<cartographer::mapping::PoseGraphInterface> pose_graph_stub_;
+  std::map<int,
+           std::unique_ptr<cartographer::mapping::TrajectoryBuilderInterface>>
       trajectory_builder_stubs_;
 };
 
 }  // namespace mapping
 }  // namespace cartographer_grpc
 
-#endif  // CARTOGRAPHER_GRPC_MAPPING_MAP_BUILDER_STUB_H_
+#endif  // CARTOGRAPHER_GRPC_CLIENT_MAP_BUILDER_STUB_H_
diff --git a/cartographer_grpc/client_server_test.cc b/cartographer_grpc/client_server_test.cc
index 320053d..fba69b3 100644
--- a/cartographer_grpc/client_server_test.cc
+++ b/cartographer_grpc/client_server_test.cc
@@ -19,9 +19,9 @@
 
 #include "cartographer/mapping/internal/test_helpers.h"
 #include "cartographer/mapping/local_slam_result_data.h"
+#include "cartographer_grpc/client/map_builder_stub.h"
 #include "cartographer_grpc/map_builder_server.h"
 #include "cartographer_grpc/map_builder_server_options.h"
-#include "cartographer_grpc/mapping/map_builder_stub.h"
 #include "cartographer_grpc/testing/mock_map_builder.h"
 #include "cartographer_grpc/testing/mock_trajectory_builder.h"
 #include "glog/logging.h"
diff --git a/cartographer_grpc/mapping/pose_graph_stub.cc b/cartographer_grpc/internal/client/pose_graph_stub.cc
similarity index 98%
rename from cartographer_grpc/mapping/pose_graph_stub.cc
rename to cartographer_grpc/internal/client/pose_graph_stub.cc
index 17c261a..684d4e1 100644
--- a/cartographer_grpc/mapping/pose_graph_stub.cc
+++ b/cartographer_grpc/internal/client/pose_graph_stub.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer_grpc/mapping/pose_graph_stub.h"
+#include "cartographer_grpc/internal/client/pose_graph_stub.h"
 #include "cartographer/mapping/pose_graph.h"
 #include "cartographer_grpc/framework/client.h"
 #include "cartographer_grpc/handlers/get_all_submap_poses.h"
diff --git a/cartographer_grpc/mapping/pose_graph_stub.h b/cartographer_grpc/internal/client/pose_graph_stub.h
similarity index 92%
rename from cartographer_grpc/mapping/pose_graph_stub.h
rename to cartographer_grpc/internal/client/pose_graph_stub.h
index 5c28929..21131e4 100644
--- a/cartographer_grpc/mapping/pose_graph_stub.h
+++ b/cartographer_grpc/internal/client/pose_graph_stub.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_GRPC_MAPPING_POSE_GRAPH_STUB_H_
-#define CARTOGRAPHER_GRPC_MAPPING_POSE_GRAPH_STUB_H_
+#ifndef CARTOGRAPHER_GRPC_INTERNAL_CLIENT_POSE_GRAPH_STUB_H_
+#define CARTOGRAPHER_GRPC_INTERNAL_CLIENT_POSE_GRAPH_STUB_H_
 
 #include "cartographer/mapping/pose_graph_interface.h"
 #include "grpc++/grpc++.h"
@@ -58,4 +58,4 @@ class PoseGraphStub : public cartographer::mapping::PoseGraphInterface {
 }  // namespace mapping
 }  // namespace cartographer_grpc
 
-#endif  // CARTOGRAPHER_GRPC_MAPPING_POSE_GRAPH_STUB_H_
+#endif  // CARTOGRAPHER_GRPC_INTERNAL_CLIENT_POSE_GRAPH_STUB_H_
diff --git a/cartographer_grpc/mapping/trajectory_builder_stub.cc b/cartographer_grpc/internal/client/trajectory_builder_stub.cc
similarity index 98%
rename from cartographer_grpc/mapping/trajectory_builder_stub.cc
rename to cartographer_grpc/internal/client/trajectory_builder_stub.cc
index 8a78afc..9351d50 100644
--- a/cartographer_grpc/mapping/trajectory_builder_stub.cc
+++ b/cartographer_grpc/internal/client/trajectory_builder_stub.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "cartographer_grpc/mapping/trajectory_builder_stub.h"
+#include "cartographer_grpc/internal/client/trajectory_builder_stub.h"
 
 #include "cartographer/mapping/local_slam_result_data.h"
 #include "cartographer_grpc/proto/map_builder_service.pb.h"
diff --git a/cartographer_grpc/mapping/trajectory_builder_stub.h b/cartographer_grpc/internal/client/trajectory_builder_stub.h
similarity index 93%
rename from cartographer_grpc/mapping/trajectory_builder_stub.h
rename to cartographer_grpc/internal/client/trajectory_builder_stub.h
index 7095ae5..cae4581 100644
--- a/cartographer_grpc/mapping/trajectory_builder_stub.h
+++ b/cartographer_grpc/internal/client/trajectory_builder_stub.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef CARTOGRAPHER_GRPC_MAPPING_TRAJECTORY_BUILDER_STUB_H_
-#define CARTOGRAPHER_GRPC_MAPPING_TRAJECTORY_BUILDER_STUB_H_
+#ifndef CARTOGRAPHER_GRPC_INTERNAL_CLIENT_TRAJECTORY_BUILDER_STUB_H_
+#define CARTOGRAPHER_GRPC_INTERNAL_CLIENT_TRAJECTORY_BUILDER_STUB_H_
 
 #include <thread>
 
@@ -30,6 +30,8 @@
 #include "cartographer_grpc/handlers/add_rangefinder_data_handler.h"
 #include "cartographer_grpc/handlers/receive_local_slam_results_handler.h"
 #include "grpc++/grpc++.h"
+#include "pose_graph_stub.h"
+#include "trajectory_builder_stub.h"
 
 namespace cartographer_grpc {
 namespace mapping {
@@ -88,4 +90,4 @@ class TrajectoryBuilderStub
 }  // namespace mapping
 }  // namespace cartographer_grpc
 
-#endif  // CARTOGRAPHER_GRPC_MAPPING_TRAJECTORY_BUILDER_STUB_H_
+#endif  // CARTOGRAPHER_GRPC_INTERNAL_CLIENT_TRAJECTORY_BUILDER_STUB_H_