diff --git a/ngc_ft1.cpp b/ngc_ft1.cpp
index c76335e..c219966 100644
--- a/ngc_ft1.cpp
+++ b/ngc_ft1.cpp
@@ -11,8 +11,10 @@
 struct NGC_FT1 {
 	NGC_FT1_options options;
 
-	std::unordered_map<NGC_FT1_file_kind, NGC_FT1_recv_request_cb*> cb_request;
-	std::unordered_map<NGC_FT1_file_kind, NGC_FT1_recv_init_cb*> cb_init;
+	std::unordered_map<NGC_FT1_file_kind, NGC_FT1_recv_request_cb*> cb_recv_request;
+	std::unordered_map<NGC_FT1_file_kind, NGC_FT1_recv_init_cb*> cb_recv_init;
+	std::unordered_map<NGC_FT1_file_kind, NGC_FT1_recv_data_cb*> cb_recv_data;
+	std::unordered_map<NGC_FT1_file_kind, NGC_FT1_send_data_cb*> cb_send_data;
 
 	struct Group {
 		struct Peer {
@@ -94,8 +96,6 @@ bool NGC_FT1_init(NGC_EXT_CTX* ngc_ext_ctx, const struct NGC_FT1_options* option
 	ngc_ext_ctx->callbacks[FT1_DATA_ACK] = nullptr;
 	ngc_ext_ctx->callbacks[FT1_DATA_FIN] = nullptr;
 	ngc_ext_ctx->callbacks[FT1_DATA_FIN_ACK] = nullptr;
-	//ngc_ext_ctx->callbacks[HS1_REQUEST_LAST_IDS] = _handle_HS1_REQUEST_LAST_IDS;
-	//ngc_ext_ctx->callbacks[HS1_RESPONSE_LAST_IDS] = _handle_HS1_RESPONSE_LAST_IDS;
 
 	return true;
 }
@@ -105,6 +105,35 @@ void NGC_FT1_kill(NGC_EXT_CTX* ngc_ext_ctx) {
 	ngc_ext_ctx->ngc_ft1_ctx = nullptr;
 }
 
+void NGC_FT1_register_callback_recv_request(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_request_cb* callback) {
+	assert(ngc_ext_ctx);
+	assert(ngc_ext_ctx->ngc_ft1_ctx);
+
+	ngc_ext_ctx->ngc_ft1_ctx->cb_recv_request[file_kind] = callback;
+}
+
+void NGC_FT1_register_callback_recv_init(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_init_cb* callback) {
+	assert(ngc_ext_ctx);
+	assert(ngc_ext_ctx->ngc_ft1_ctx);
+
+	ngc_ext_ctx->ngc_ft1_ctx->cb_recv_init[file_kind] = callback;
+}
+
+void NGC_FT1_register_callback_recv_data(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_data_cb* callback) {
+	assert(ngc_ext_ctx);
+	assert(ngc_ext_ctx->ngc_ft1_ctx);
+
+	ngc_ext_ctx->ngc_ft1_ctx->cb_recv_data[file_kind] = callback;
+}
+
+void NGC_FT1_register_callback_send_data(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_send_data_cb* callback) {
+	assert(ngc_ext_ctx);
+	assert(ngc_ext_ctx->ngc_ft1_ctx);
+
+	ngc_ext_ctx->ngc_ft1_ctx->cb_send_data[file_kind] = callback;
+}
+
+
 // iterate
 
 void NGC_FT1_send_request(
@@ -145,14 +174,6 @@ void NGC_FT1_send_request_private(
 	_send_pkg_FT1_REQUEST(tox, group_number, peer_number, file_kind, file_id, file_id_size);
 }
 
-void NGC_FT1_register_callback_recv_request(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_request_cb* callback) {
-	assert(ngc_ext_ctx);
-	assert(ngc_ext_ctx->ngc_ft1_ctx);
-
-	ngc_ext_ctx->ngc_ft1_ctx->cb_request[file_kind] = callback;
-}
-
-
 bool NGC_FT1_send_init_private(
 	Tox *tox, NGC_EXT_CTX* ngc_ext_ctx,
 	uint32_t group_number, uint32_t peer_number,
@@ -205,13 +226,6 @@ bool NGC_FT1_send_init_private(
 	return true;
 }
 
-void NGC_FT1_register_callback_recv_init(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_init_cb* callback) {
-	assert(ngc_ext_ctx);
-	assert(ngc_ext_ctx->ngc_ft1_ctx);
-
-	ngc_ext_ctx->ngc_ft1_ctx->cb_init[file_kind] = callback;
-}
-
 static bool _send_pkg_FT1_REQUEST(const Tox* tox, uint32_t group_number, uint32_t peer_number, uint8_t file_kind, const uint8_t* file_id, size_t file_id_size) {
 	// - 1 byte packet id
 	// - 1 byte (TODO: more?) file_kind
@@ -341,8 +355,8 @@ static void _handle_FT1_REQUEST(
 	fprintf(stderr, "]\n");
 
 	NGC_FT1_recv_request_cb* fn_ptr = nullptr;
-	if (ngc_ext_ctx->ngc_ft1_ctx->cb_request.count(file_kind)) {
-		fn_ptr = ngc_ext_ctx->ngc_ft1_ctx->cb_request.at(file_kind);
+	if (ngc_ext_ctx->ngc_ft1_ctx->cb_recv_request.count(file_kind)) {
+		fn_ptr = ngc_ext_ctx->ngc_ft1_ctx->cb_recv_request.at(file_kind);
 	}
 	if (fn_ptr) {
 		fn_ptr(tox, ngc_ext_ctx, group_number, peer_number, data+curser, length-curser);
@@ -396,8 +410,8 @@ static void _handle_FT1_INIT(
 	// did we allready ack this and the other side just did not see the ack?
 
 	NGC_FT1_recv_init_cb* fn_ptr = nullptr;
-	if (ngc_ext_ctx->ngc_ft1_ctx->cb_init.count(file_kind)) {
-		fn_ptr = ngc_ext_ctx->ngc_ft1_ctx->cb_init.at(file_kind);
+	if (ngc_ext_ctx->ngc_ft1_ctx->cb_recv_init.count(file_kind)) {
+		fn_ptr = ngc_ext_ctx->ngc_ft1_ctx->cb_recv_init.at(file_kind);
 	}
 	bool accept_ft;
 	if (fn_ptr) {
diff --git a/ngc_ft1.h b/ngc_ft1.h
index c815283..8d5268b 100644
--- a/ngc_ft1.h
+++ b/ngc_ft1.h
@@ -89,6 +89,17 @@ typedef bool NGC_FT1_recv_init_cb(Tox *tox, NGC_EXT_CTX* ngc_ext_ctx, uint32_t g
 
 void NGC_FT1_register_callback_recv_init(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_init_cb* callback);
 
+// ========== data ==========
+
+typedef void NGC_FT1_recv_data_cb(Tox *tox, NGC_EXT_CTX* ngc_ext_ctx, uint32_t group_number, uint32_t peer_number, uint8_t transfer_id, size_t data_offset, const uint8_t* data, size_t data_size);
+
+void NGC_FT1_register_callback_recv_data(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_recv_data_cb* callback);
+
+typedef void NGC_FT1_send_data_cb(Tox *tox, NGC_EXT_CTX* ngc_ext_ctx, uint32_t group_number, uint32_t peer_number, uint8_t transfer_id, size_t data_offset, uint8_t** data, size_t* data_size);
+
+void NGC_FT1_register_callback_send_data(NGC_EXT_CTX* ngc_ext_ctx, NGC_FT1_file_kind file_kind, NGC_FT1_send_data_cb* callback);
+
+
 // ========== peer online/offline ==========
 //void NGC_FT1_peer_online(Tox* tox, NGC_FT1* ngc_hs1_ctx, uint32_t group_number, uint32_t peer_number, bool online);