diff --git a/src/ipc.cc b/src/ipc.cc
index d20240e3..495ad307 100644
--- a/src/ipc.cc
+++ b/src/ipc.cc
@@ -104,3 +104,7 @@ const char* IpcIdToString(IpcId id) {
 BaseIpcMessage::BaseIpcMessage(IpcId method_id) : method_id(method_id) {}
 
 BaseIpcMessage::~BaseIpcMessage() = default;
+
+lsRequestId BaseIpcMessage::GetRequestId() {
+  return std::monostate();
+}
diff --git a/src/ipc.h b/src/ipc.h
index 7326e3a6..400e1b4b 100644
--- a/src/ipc.h
+++ b/src/ipc.h
@@ -75,6 +75,8 @@ struct BaseIpcMessage {
   BaseIpcMessage(IpcId method_id);
   virtual ~BaseIpcMessage();
 
+  virtual lsRequestId GetRequestId();
+
   template <typename T>
   T* As() {
     assert(method_id == T::kIpcId);
@@ -87,6 +89,10 @@ struct RequestMessage : public BaseIpcMessage {
   // number | string, actually no null
   lsRequestId id;
   RequestMessage() : BaseIpcMessage(T::kIpcId) {}
+
+  lsRequestId GetRequestId() override {
+    return id;
+  }
 };
 
 // NotificationMessage does not have |id|.