diff --git a/CMakeLists.txt b/CMakeLists.txt
index f842662..a00b77c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -28,11 +28,13 @@ configure_file(
 
 set(BUILD_EXAMPLES OFF)
 set(SPNG_SHARED OFF)
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 add_subdirectory(external/libspng EXCLUDE_FROM_ALL)
 
 set(RTMIDI_API_JACK OFF)
 set(RTMIDI_BUILD_STATIC_LIBS ON)
 add_subdirectory(external/rtmidi EXCLUDE_FROM_ALL)
+add_subdirectory(src/midi)
 
 set(sources
     ${g_font_cpp_path}
@@ -66,10 +68,6 @@ set(sources
     src/ResourceLoader.cpp
     src/Theme.cpp
     src/Version.cpp
-    src/midi/InputObserver.cpp
-    src/midi/MidiEngine.cpp
-    src/midi/MidiProbe.cpp
-    src/midi/OutputObserver.cpp
 )
 
 if(WIN32)
@@ -105,7 +103,8 @@ target_link_libraries(midiconn PRIVATE
     SDL2::SDL2
     fmt::fmt
     freetype
-    resources)
+    resources
+    midi)
 if(NOT WIN32 AND MC_CHECK_FOR_UPDATES)
     target_link_libraries(midiconn PRIVATE curl)
 endif()
@@ -113,7 +112,6 @@ target_compile_definitions(midiconn PRIVATE
     SPDLOG_ACTIVE_LEVEL=SPDLOG_LEVEL_DEBUG
     IMGUI_ENABLE_FREETYPE
 )
-target_compile_features(midiconn PRIVATE cxx_std_20)
 
 set(CPACK_PACKAGE_NAME "midiconn")
 set(CPACK_PACKAGE_VENDOR "safeworlds")
diff --git a/src/midi/CMakeLists.txt b/src/midi/CMakeLists.txt
new file mode 100644
index 0000000..8d79a26
--- /dev/null
+++ b/src/midi/CMakeLists.txt
@@ -0,0 +1,10 @@
+add_library(midi 
+    InputObserver.cpp
+    MidiEngine.cpp
+    MidiGraph.cpp
+    MidiProbe.cpp
+    OutputObserver.cpp
+)
+
+target_compile_features(midi PUBLIC cxx_std_20)
+target_link_libraries(midi PRIVATE fmt::fmt rtmidi spdlog::spdlog)
diff --git a/src/midi/MidiGraph.cpp b/src/midi/MidiGraph.cpp
new file mode 100644
index 0000000..3fdedcc
--- /dev/null
+++ b/src/midi/MidiGraph.cpp
@@ -0,0 +1,88 @@
+#include "MidiGraph.hpp"
+
+namespace mc::midi
+{
+
+Node::~Node()
+{
+    for (auto& conn : m_sender_connections)
+    {
+        Connection::destroy(conn);
+    }
+    for (auto& conn : m_receiver_connections)
+    {
+        Connection::destroy(conn);
+    }
+}
+
+void Node::process(data_span data)
+{
+}
+
+void Node::broadcast_data(data_span data)
+{
+    size_t idx = 0;
+    for (auto it = m_sender_connections.begin(), end = m_sender_connections.end(); it != end;
+         ++it, ++idx)
+    {
+        if (idx == 0)
+        {
+            (*it)->receiver()->receive_data(data);
+        }
+        else
+        {
+            data_vec data_copy(data.size());
+            std::copy(data.begin(), data.end(), data_copy.begin());
+            (*it)->receiver()->receive_data(data_copy);
+        }
+    }
+}
+
+void Node::connect_as_sender(connection_ptr connection)
+{
+    m_sender_connections.emplace(connection);
+}
+
+void Node::connect_as_receiver(connection_ptr connection)
+{
+    m_receiver_connections.emplace(connection);
+}
+
+void Node::remove_connection(connection_ptr connection)
+{
+    remove_connection_impl(m_sender_connections, connection);
+    remove_connection_impl(m_receiver_connections, connection);
+}
+
+void Node::remove_connection_impl(std::set<connection_ptr>& set, connection_ptr connection)
+{
+    set.erase(connection);
+}
+
+void Node::receive_data(data_span data)
+{
+    process(data);
+    broadcast_data(data);
+}
+
+weak_connection_ptr Connection::create(Node& sender, Node& receiver)
+{
+    const auto conn  = std::shared_ptr<Connection>(new Connection());
+    conn->m_sender   = &sender;
+    conn->m_receiver = &receiver;
+    sender.connect_as_sender(conn);
+    receiver.connect_as_receiver(conn);
+    return conn;
+}
+
+void Connection::destroy(weak_connection_ptr connection)
+{
+    auto connection_shared = connection.lock();
+    if (connection_shared)
+    {
+        connection_shared->m_sender->remove_connection(connection_shared);
+        connection_shared->m_receiver->remove_connection(connection_shared);
+    }
+}
+
+} // namespace mc::midi
diff --git a/src/midi/MidiGraph.hpp b/src/midi/MidiGraph.hpp
new file mode 100644
index 0000000..e21260d
--- /dev/null
+++ b/src/midi/MidiGraph.hpp
@@ -0,0 +1,61 @@
+#pragma once
+
+#include <algorithm>
+#include <memory>
+#include <set>
+#include <span>
+#include <vector>
+
+namespace mc::midi
+{
+
+class Connection;
+
+using connection_ptr      = std::shared_ptr<Connection>;
+using weak_connection_ptr = std::weak_ptr<Connection>;
+using data_vec = std::vector<unsigned char>;
+using data_span = std::span<unsigned char>;
+
+class Node
+{
+public:
+    virtual ~Node();
+
+protected:
+    virtual void process(data_span data);
+    void broadcast_data(data_span data);
+
+private:
+    friend class Connection;
+
+    void connect_as_sender(connection_ptr connection);
+    void connect_as_receiver(connection_ptr connection);
+    void remove_connection(connection_ptr connection);
+    void remove_connection_impl(std::set<connection_ptr>& set, connection_ptr connection);
+
+    void receive_data(data_span data);
+
+    std::set<connection_ptr> m_sender_connections;
+    std::set<connection_ptr> m_receiver_connections;
+};
+
+class Connection final
+{
+private:
+    Connection() = default;
+
+public:
+    static weak_connection_ptr create(Node& sender, Node& receiver);
+    static void                destroy(weak_connection_ptr connection);
+
+    Node* receiver() const
+    {
+        return m_receiver;
+    }
+
+private:
+    Node* m_sender;
+    Node* m_receiver;
+};
+
+} // namespace mc::midi