diff --git a/cartographer_grpc/handlers/add_trajectory_handler.h b/cartographer_grpc/handlers/add_trajectory_handler.h
new file mode 100644
index 0000000..fb25fd4
--- /dev/null
+++ b/cartographer_grpc/handlers/add_trajectory_handler.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2017 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CARTOGRAPHER_GRPC_HANDLERS_ADD_TRAJECTORY_HANDLER_H
+#define CARTOGRAPHER_GRPC_HANDLERS_ADD_TRAJECTORY_HANDLER_H
+
+#include "cartographer/common/make_unique.h"
+#include "cartographer_grpc/framework/rpc_handler.h"
+#include "cartographer_grpc/map_builder_server.h"
+#include "cartographer_grpc/proto/map_builder_service.pb.h"
+
+namespace cartographer_grpc {
+namespace handlers {
+
+class AddTrajectoryHandler
+    : public framework::RpcHandler<proto::AddTrajectoryRequest,
+                                   proto::AddTrajectoryResponse> {
+ public:
+  void OnRequest(const proto::AddTrajectoryRequest& request) override {
+    const int trajectory_id =
+        GetContext<MapBuilderServer::MapBuilderContext>()
+            ->map_builder()
+            .AddTrajectoryBuilder(std::unordered_set<std::string>(
+                                      request.expected_sensor_ids().begin(),
+                                      request.expected_sensor_ids().end()),
+                                  request.trajectory_builder_options(),
+                                  nullptr /* local_slam_result_callback */);
+    auto response =
+        cartographer::common::make_unique<proto::AddTrajectoryResponse>();
+    response->set_trajectory_id(trajectory_id);
+    Send(std::move(response));
+  }
+};
+
+}  // namespace handlers
+}  // namespace cartographer_grpc
+
+#endif  // CARTOGRAPHER_GRPC_HANDLERS_ADD_TRAJECTORY_HANDLER_H
diff --git a/cartographer_grpc/handlers/finish_trajectory_handler.h b/cartographer_grpc/handlers/finish_trajectory_handler.h
new file mode 100644
index 0000000..30ff31f
--- /dev/null
+++ b/cartographer_grpc/handlers/finish_trajectory_handler.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2017 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CARTOGRAPHER_GRPC_HANDLERS_FINISH_TRAJECTORY_HANDLER_H
+#define CARTOGRAPHER_GRPC_HANDLERS_FINISH_TRAJECTORY_HANDLER_H
+
+#include "cartographer/common/make_unique.h"
+#include "cartographer_grpc/framework/rpc_handler.h"
+#include "cartographer_grpc/map_builder_server.h"
+#include "cartographer_grpc/proto/map_builder_service.pb.h"
+#include "google/protobuf/empty.pb.h"
+
+namespace cartographer_grpc {
+namespace handlers {
+
+class FinishTrajectoryHandler
+    : public framework::RpcHandler<proto::FinishTrajectoryRequest,
+                                   google::protobuf::Empty> {
+ public:
+  void OnRequest(const proto::FinishTrajectoryRequest& request) override {
+    GetContext<MapBuilderServer::MapBuilderContext>()
+        ->map_builder()
+        .FinishTrajectory(request.trajectory_id());
+    Send(std::move(
+        cartographer::common::make_unique<google::protobuf::Empty>()));
+  }
+};
+
+}  // namespace handlers
+}  // namespace cartographer_grpc
+
+#endif  // CARTOGRAPHER_GRPC_HANDLERS_FINISH_TRAJECTORY_HANDLER_H
diff --git a/cartographer_grpc/map_builder_server.cc b/cartographer_grpc/map_builder_server.cc
index d2aa330..da445ba 100644
--- a/cartographer_grpc/map_builder_server.cc
+++ b/cartographer_grpc/map_builder_server.cc
@@ -15,6 +15,8 @@
  */
 #include "cartographer_grpc/map_builder_server.h"
 
+#include "cartographer_grpc/handlers/add_trajectory_handler.h"
+#include "cartographer_grpc/handlers/finish_trajectory_handler.h"
 #include "cartographer_grpc/proto/map_builder_service.grpc.pb.h"
 #include "glog/logging.h"
 
@@ -27,6 +29,10 @@ MapBuilderServer::MapBuilderServer(
   server_builder.SetServerAddress(map_builder_server_options.server_address());
   server_builder.SetNumberOfThreads(
       map_builder_server_options.num_grpc_threads());
+  server_builder.RegisterHandler<handlers::AddTrajectoryHandler,
+                                 proto::MapBuilderService>("AddTrajectory");
+  server_builder.RegisterHandler<handlers::FinishTrajectoryHandler,
+                                 proto::MapBuilderService>("FinishTrajectory");
   grpc_server_ = server_builder.Build();
   grpc_server_->SetExecutionContext(
       cartographer::common::make_unique<MapBuilderContext>(&map_builder_));