diff --git a/autoware_adapi_v1_msgs/CMakeLists.txt b/autoware_adapi_v1_msgs/CMakeLists.txt
index d0b56ae..77b93a0 100644
--- a/autoware_adapi_v1_msgs/CMakeLists.txt
+++ b/autoware_adapi_v1_msgs/CMakeLists.txt
@@ -40,6 +40,7 @@ rosidl_generate_interfaces(${PROJECT_NAME}
   planning/srv/SetCooperationPolicies.srv
   planning/srv/GetCooperationPolicies.srv
   system/msg/MrmState.msg
+  system/msg/Heartbeat.msg
   vehicle/msg/DoorCommand.msg
   vehicle/msg/DoorLayout.msg
   vehicle/msg/DoorStatus.msg
diff --git a/autoware_adapi_v1_msgs/system/msg/Heartbeat.msg b/autoware_adapi_v1_msgs/system/msg/Heartbeat.msg
new file mode 100644
index 0000000..c6be5ba
--- /dev/null
+++ b/autoware_adapi_v1_msgs/system/msg/Heartbeat.msg
@@ -0,0 +1,5 @@
+# Timestamp in Autoware for delay checking.
+builtin_interfaces/Time stamp
+
+# Sequence number for order verification, wraps at 65535.
+uint16 seq