diff --git a/Tools/msg/templates/ucdr/msg.h.em b/Tools/msg/templates/ucdr/msg.h.em
index 5f68b9256e..d9cbc839f4 100644
--- a/Tools/msg/templates/ucdr/msg.h.em
+++ b/Tools/msg/templates/ucdr/msg.h.em
@@ -124,8 +124,9 @@ static inline constexpr int ucdr_topic_size_@(topic)()
 	return @(struct_size);
 }
 
-bool ucdr_serialize_@(topic)(const @(uorb_struct)& topic, ucdrBuffer& buf, int64_t time_offset = 0)
+bool ucdr_serialize_@(topic)(const void* data, ucdrBuffer& buf, int64_t time_offset = 0)
 {
+	const @(uorb_struct)& topic = *static_cast<const @(uorb_struct)*>(data);
 @{
 for field_type, field_name, field_size, padding in fields:
 	if padding > 0:
diff --git a/src/modules/uxrce_dds_client/dds_topics.h.em b/src/modules/uxrce_dds_client/dds_topics.h.em
index bcbc908d3a..0addb6b903 100644
--- a/src/modules/uxrce_dds_client/dds_topics.h.em
+++ b/src/modules/uxrce_dds_client/dds_topics.h.em
@@ -27,12 +27,33 @@ import os
 #include <uORB/ucdr/@(include).h>
 @[end for]@
 
+typedef bool (*UcdrSerializeMethod)(const void* data, ucdrBuffer& buf, int64_t time_offset);
+
+static constexpr int max_topic_size = 512;
+@[    for pub in publications]@
+static_assert(sizeof(@(pub['simple_base_type'])_s) <= max_topic_size, "topic too large, increase max_topic_size");
+@[    end for]@
+
+struct SendSubscription {
+	uORB::Subscription subscription;
+	uxrObjectId data_writer;
+	const char* dds_type_name;
+	uint32_t topic_size;
+	UcdrSerializeMethod ucdr_serialize_method;
+};
+
 // Subscribers for messages to send
 struct SendTopicsSubs {
+	SendSubscription send_subscriptions[@(len(publications))] = {
 @[    for pub in publications]@
-	uORB::Subscription @(pub['topic_simple'])_sub{ORB_ID(@(pub['topic_simple']))};
-	uxrObjectId @(pub['topic_simple'])_data_writer{};
+			{ uORB::Subscription(ORB_ID(@(pub['topic_simple']))),
+			  uxr_object_id(0, UXR_INVALID_ID),
+			  "@(pub['dds_type'])",
+			  ucdr_topic_size_@(pub['simple_base_type'])(),
+			  &ucdr_serialize_@(pub['simple_base_type']),
+			},
 @[    end for]@
+	};
 
 	uint32_t num_payload_sent{};
 
@@ -42,47 +63,45 @@ struct SendTopicsSubs {
 
 void SendTopicsSubs::reset() {
 	num_payload_sent = 0;
-@[    for idx, pub in enumerate(publications)]@
-	@(pub['topic_simple'])_data_writer = uxr_object_id(0, UXR_INVALID_ID);
-@[    end for]@
+	for (unsigned idx = 0; idx < sizeof(send_subscriptions)/sizeof(send_subscriptions[0]); ++idx) {
+		send_subscriptions[idx].data_writer = uxr_object_id(0, UXR_INVALID_ID);
+	}
 };
 
 void SendTopicsSubs::update(uxrSession *session, uxrStreamId reliable_out_stream_id, uxrStreamId best_effort_stream_id, uxrObjectId participant_id, const char *client_namespace)
 {
 	int64_t time_offset_us = session->time_offset / 1000; // ns -> us
-@[    for idx, pub in enumerate(publications)]@
 
-	{
-		@(pub['simple_base_type'])_s data;
+	alignas(sizeof(uint64_t)) char topic_data[max_topic_size];
 
-		if (@(pub['topic_simple'])_sub.update(&data)) {
-
-			if (@(pub['topic_simple'])_data_writer.id == UXR_INVALID_ID) {
+	for (unsigned idx = 0; idx < sizeof(send_subscriptions)/sizeof(send_subscriptions[0]); ++idx) {
+		if (send_subscriptions[idx].subscription.update(&topic_data)) {
+			if (send_subscriptions[idx].data_writer.id == UXR_INVALID_ID) {
 				// data writer not created yet
-				create_data_writer(session, reliable_out_stream_id, participant_id, ORB_ID::@(pub['topic_simple']), client_namespace, "@(pub['topic_simple'])", "@(pub['dds_type'])", @(pub['topic_simple'])_data_writer);
+				create_data_writer(session, reliable_out_stream_id, participant_id, send_subscriptions[idx].subscription.orb_id(), client_namespace, send_subscriptions[idx].subscription.get_topic()->o_name,
+								   send_subscriptions[idx].dds_type_name, send_subscriptions[idx].data_writer);
 			}
 
-			if (@(pub['topic_simple'])_data_writer.id != UXR_INVALID_ID) {
+			if (send_subscriptions[idx].data_writer.id != UXR_INVALID_ID) {
 
 				ucdrBuffer ub;
-				uint32_t topic_size = ucdr_topic_size_@(pub['simple_base_type'])();
-				if (uxr_prepare_output_stream(session, best_effort_stream_id, @(pub['topic_simple'])_data_writer, &ub, topic_size) != UXR_INVALID_REQUEST_ID) {
-					ucdr_serialize_@(pub['simple_base_type'])(data, ub, time_offset_us);
+				uint32_t topic_size = send_subscriptions[idx].topic_size;
+				if (uxr_prepare_output_stream(session, best_effort_stream_id, send_subscriptions[idx].data_writer, &ub, topic_size) != UXR_INVALID_REQUEST_ID) {
+					send_subscriptions[idx].ucdr_serialize_method(&topic_data, ub, time_offset_us);
 					// TODO: fill up the MTU and then flush, which reduces the packet overhead
 					uxr_flash_output_streams(session);
 					num_payload_sent += topic_size;
 
 				} else {
-					//PX4_ERR("Error uxr_prepare_output_stream UXR_INVALID_REQUEST_ID @(pub['topic_simple'])");
+					//PX4_ERR("Error uxr_prepare_output_stream UXR_INVALID_REQUEST_ID %s", send_subscriptions[idx].subscription.get_topic()->o_name);
 				}
 
 			} else {
-				//PX4_ERR("Error UXR_INVALID_ID @(pub['topic_simple'])");
+				//PX4_ERR("Error UXR_INVALID_ID %s", send_subscriptions[idx].subscription.get_topic()->o_name);
 			}
 
 		}
 	}
-@[    end for]@
 }
 
 // Publishers for received messages