diff --git a/libmxclient/callback.go b/libmxclient/callback.go
new file mode 100644
index 0000000..fd6bfd3
--- /dev/null
+++ b/libmxclient/callback.go
@@ -0,0 +1,31 @@
+// Copyright (C) 2026 saces@c-base.org
+// SPDX-License-Identifier: AGPL-3.0-only
+package main
+
+/*
+#include <stdlib.h>
+typedef void (*on_event_handler_ptr) (char*);
+typedef void (*on_message_handler_ptr) (char*);
+
+static inline void call_c_on_event_handler(on_event_handler_ptr ptr, char* jsonStr) {
+    (ptr)(jsonStr);
+}
+
+static inline void call_c_on_message_handler(on_message_handler_ptr ptr, char* jsonStr) {
+    (ptr)(jsonStr);
+}
+*/
+import "C"
+
+var on_event_handler C.on_event_handler_ptr
+var on_message_handler C.on_message_handler_ptr
+
+//export register_on_event_handler
+func register_on_event_handler(fn C.on_event_handler_ptr) {
+	on_event_handler = fn
+}
+
+//export register_on_message_handler
+func register_on_message_handler(fn C.on_message_handler_ptr) {
+	on_message_handler = fn
+}
diff --git a/pygomx/build_ffi.py b/pygomx/build_ffi.py
index 64feb06..0893b6e 100644
--- a/pygomx/build_ffi.py
+++ b/pygomx/build_ffi.py
@@ -13,6 +13,10 @@ ffibuilder.set_source(
 
 ffibuilder.cdef(
     csource="""
+    typedef void (*on_event_handler_ptr) (char*);
+    typedef void (*on_message_handler_ptr) (char*);
+    extern void  register_on_event_handler(on_event_handler_ptr ptr);
+    extern void  register_on_message_handler(on_message_handler_ptr ptr);
     extern void  FreeCString(char * s);
     extern char* cli_discoverhs(char* mxid);
     extern char* cli_mkmxtoken(char* mxid, char* pw);