diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4bc6c63..9acd1e3 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -19,6 +19,18 @@ target_link_libraries(fragment_store PUBLIC
 
 ########################################
 
+add_library(message_fragment_store
+	./fragment_store/message_fragment_store.hpp
+	./fragment_store/message_fragment_store.cpp
+)
+target_compile_features(message_fragment_store PRIVATE cxx_std_20)
+target_link_libraries(message_fragment_store PUBLIC
+	fragment_store
+	solanaceae_message3
+)
+
+########################################
+
 add_executable(fragment_store_test
 	fragment_store/test_fragstore.cpp
 )
@@ -112,6 +124,7 @@ target_link_libraries(tomato PUBLIC
 	solanaceae_tox_messages
 
 	fragment_store
+	message_fragment_store
 
 	SDL3::SDL3
 
diff --git a/src/fragment_store/message_fragment_store.cpp b/src/fragment_store/message_fragment_store.cpp
new file mode 100644
index 0000000..2f1324c
--- /dev/null
+++ b/src/fragment_store/message_fragment_store.cpp
@@ -0,0 +1,131 @@
+#include "./message_fragment_store.hpp"
+
+#include <solanaceae/message3/components.hpp>
+
+#include <nlohmann/json.hpp>
+
+#include <cstdint>
+#include <cassert>
+
+static bool serl_json_msg_ts_range(void* comp, nlohmann::json& out) {
+	if (comp == nullptr) {
+		return false;
+	}
+
+	out = nlohmann::json::object();
+
+	auto& r_comp = *reinterpret_cast<FragComp::MessagesTSRange*>(comp);
+
+	out["begin"] = r_comp.begin;
+	out["end"] = r_comp.end;
+
+	return true;
+}
+
+void MessageFragmentStore::handleMessage(const Message3Handle& m) {
+	if (!static_cast<bool>(m)) {
+		return; // huh?
+	}
+
+	if (!m.all_of<Message::Components::Timestamp>()) {
+		return; // we only handle msg with ts
+	}
+
+	const auto msg_ts = m.get<Message::Components::Timestamp>().ts;
+
+	if (!m.all_of<Message::Components::FUID>()) {
+		// missing fuid
+		// find closesed non-sealed off fragment
+
+		std::vector<uint8_t> fragment_uid;
+
+		// first search for fragment where the ts falls into the range
+		for (const auto& [tsrage, fid] : _fuid_open) {
+			if (tsrage.ts_begin <= msg_ts && tsrage.ts_end >= msg_ts) {
+				fragment_uid = fid;
+				// TODO: check conditions for open here
+				// TODO: mark msg (and frag?) dirty
+			}
+		}
+
+		// if it did not fit into an existing fragment, we next look for fragments that could be extended
+		if (fragment_uid.empty()) {
+			for (const auto& [tsrage, fid] : _fuid_open) {
+				const int64_t frag_range = int64_t(tsrage.ts_end) - int64_t(tsrage.ts_begin);
+				//constexpr static int64_t max_frag_ts_extent {1000*60*60};
+				constexpr static int64_t max_frag_ts_extent {1000*60*3}; // 3min for testing
+				const int64_t possible_extention = max_frag_ts_extent - frag_range;
+
+				// which direction
+				if ((tsrage.ts_begin - possible_extention) <= msg_ts) {
+					fragment_uid = fid;
+					auto fh = _fs.fragmentHandle(_fs.getFragmentByID(fid));
+					assert(static_cast<bool>(fh));
+
+					// assuming ts range exists
+					auto& fts_comp = fh.get<FragComp::MessagesTSRange>();
+					fts_comp.begin = msg_ts; // extend into the past
+
+					// TODO: check conditions for open here
+					// TODO: mark msg (and frag?) dirty
+				} else if ((tsrage.ts_end + possible_extention) >= msg_ts) {
+					fragment_uid = fid;
+					auto fh = _fs.fragmentHandle(_fs.getFragmentByID(fid));
+					assert(static_cast<bool>(fh));
+
+					// assuming ts range exists
+					auto& fts_comp = fh.get<FragComp::MessagesTSRange>();
+					fts_comp.end = msg_ts; // extend into the future
+
+					// TODO: check conditions for open here
+					// TODO: mark msg (and frag?) dirty
+				}
+			}
+		}
+
+		// if its still not found, we need a new fragment
+		if (fragment_uid.empty()) {
+		}
+
+		// if this is still empty, something is very wrong and we exit here
+		if (fragment_uid.empty()) {
+			return;
+		}
+
+		m.emplace<Message::Components::FUID>(fragment_uid);
+	}
+
+	// TODO: do we use fid?
+
+	// on new message: assign fuid
+	// on new and update: mark as fragment dirty
+}
+
+MessageFragmentStore::MessageFragmentStore(
+	RegistryMessageModel& rmm,
+	FragmentStore& fs
+) : _rmm(rmm), _fs(fs) {
+	_rmm.subscribe(this, RegistryMessageModel_Event::message_construct);
+	_rmm.subscribe(this, RegistryMessageModel_Event::message_updated);
+	_rmm.subscribe(this, RegistryMessageModel_Event::message_destroy);
+
+	_fs._sc.registerSerializerJson<FragComp::MessagesTSRange>(serl_json_msg_ts_range);
+}
+
+MessageFragmentStore::~MessageFragmentStore(void) {
+}
+
+float MessageFragmentStore::tick(float time_delta) {
+	return 1000.f*60.f*60.f;
+}
+
+bool MessageFragmentStore::onEvent(const Message::Events::MessageConstruct& e) {
+	handleMessage(e.e);
+	return false;
+}
+
+bool MessageFragmentStore::onEvent(const Message::Events::MessageUpdated& e) {
+	handleMessage(e.e);
+	return false;
+}
+
diff --git a/src/fragment_store/message_fragment_store.hpp b/src/fragment_store/message_fragment_store.hpp
new file mode 100644
index 0000000..aca4d50
--- /dev/null
+++ b/src/fragment_store/message_fragment_store.hpp
@@ -0,0 +1,66 @@
+#pragma once
+
+#include "./meta_components.hpp"
+#include "./fragment_store_i.hpp"
+#include "./fragment_store.hpp"
+
+#include <cstdint>
+#include <entt/entity/registry.hpp>
+#include <entt/container/dense_map.hpp>
+
+#include <solanaceae/message3/registry_message_model.hpp>
+
+#include <map>
+
+namespace Message::Components {
+
+	using FUID = FragComp::ID;
+
+	struct FID {
+		FragmentID fid {entt::null};
+	};
+
+} // Message::Components
+
+namespace Fragment::Components {
+	struct MessagesTSRange {
+		// timestamp range within the fragment
+		uint64_t begin {0};
+		uint64_t end {0};
+	};
+} // Fragment::Components
+
+// handles fragments for messages
+// on new message: assign fuid
+// on new and update: mark as fragment dirty
+// on delete: mark as fragment dirty?
+class MessageFragmentStore : public RegistryMessageModelEventI {
+	protected:
+		RegistryMessageModel& _rmm;
+		FragmentStore& _fs;
+
+		void handleMessage(const Message3Handle& m);
+
+		struct TSRange final {
+			uint64_t ts_begin {0};
+			uint64_t ts_end {0};
+		};
+		// only contains fragments with <1024 messages and <28h tsrage
+		std::map<TSRange, std::vector<uint8_t>> _fuid_open;
+
+		std::map<uint64_t, std::vector<uint8_t>> _fuid_save_queue;
+
+	public:
+		MessageFragmentStore(
+			RegistryMessageModel& rmm,
+			FragmentStore& fs
+		);
+		virtual ~MessageFragmentStore(void);
+
+		float tick(float time_delta);
+
+	protected: // rmm
+		bool onEvent(const Message::Events::MessageConstruct& e) override;
+		bool onEvent(const Message::Events::MessageUpdated& e) override;
+};
+
diff --git a/src/main_screen.cpp b/src/main_screen.cpp
index 9db04a3..9e00875 100644
--- a/src/main_screen.cpp
+++ b/src/main_screen.cpp
@@ -14,6 +14,7 @@ MainScreen::MainScreen(SDL_Renderer* renderer_, std::string save_path, std::stri
 	renderer(renderer_),
 	rmm(cr),
 	mts(rmm),
+	mfs(rmm, fs),
 	tc(save_path, save_password),
 	tpi(tc.getTox()),
 	ad(tc),
diff --git a/src/main_screen.hpp b/src/main_screen.hpp
index aabcb51..39baf7e 100644
--- a/src/main_screen.hpp
+++ b/src/main_screen.hpp
@@ -7,6 +7,7 @@
 #include <solanaceae/contact/contact_model3.hpp>
 #include <solanaceae/message3/registry_message_model.hpp>
 #include <solanaceae/message3/message_time_sort.hpp>
+#include "./fragment_store/message_fragment_store.hpp"
 #include <solanaceae/plugin/plugin_manager.hpp>
 #include <solanaceae/toxcore/tox_event_logger.hpp>
 #include "./tox_private_impl.hpp"
@@ -50,6 +51,7 @@ struct MainScreen final : public Screen {
 	Contact3Registry cr;
 	RegistryMessageModel rmm;
 	MessageTimeSort mts;
+	MessageFragmentStore mfs;
 
 	ToxEventLogger tel{std::cout};
 	ToxClient tc;