diff --git a/.gitignore b/.gitignore
index 95b4aa7..8257f79 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,13 @@
 ref_arch.pdf
+build/
+.cache/
+CMakeUserPresets.json
+compile_commands.json
+.vcpkg/
+vcpkg_installed/
+node_modules/
+web/dist/
+*.o
+*.a
+*.so
+*.d
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..fb1da31
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,31 @@
+cmake_minimum_required(VERSION 3.24 FATAL_ERROR)
+
+project(dmf-studio
+    VERSION 0.1.0
+    LANGUAGES CXX C
+)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+option(DMF_BUILD_TESTS "Build tests" ON)
+option(DMF_BUILD_MXL_TOOLS "Build MXL tools (testsrc, sink)" OFF)
+
+find_package(fmt CONFIG REQUIRED)
+find_package(spdlog CONFIG REQUIRED)
+find_package(nlohmann_json CONFIG REQUIRED)
+find_package(Libwebsockets CONFIG REQUIRED)
+find_package(Catch2 CONFIG QUIET)
+
+add_subdirectory(extern/mxl)
+add_subdirectory(libs/dmf-node)
+add_subdirectory(libs/dmf-engine)
+add_subdirectory(nodes/passthrough)
+add_subdirectory(engine)
+
+if(DMF_BUILD_TESTS AND Catch2_FOUND)
+    add_subdirectory(tests)
+endif()
diff --git a/engine/CMakeLists.txt b/engine/CMakeLists.txt
new file mode 100644
index 0000000..3410370
--- /dev/null
+++ b/engine/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_executable(dmf-studio-engine
+    src/main.cpp
+)
+
+target_link_libraries(dmf-studio-engine PRIVATE dmf-engine)
diff --git a/engine/src/main.cpp b/engine/src/main.cpp
new file mode 100644
index 0000000..0da0b69
--- /dev/null
+++ b/engine/src/main.cpp
@@ -0,0 +1,46 @@
+#include <dmf-engine/api_server.hpp>
+#include <dmf-engine/graph.hpp>
+#include <dmf-engine/flow_manager.hpp>
+#include <dmf-engine/process_manager.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <csignal>
+#include <atomic>
+
+static std::atomic<bool> g_running{true};
+
+static void signal_handler(int /*signum*/) {
+    g_running = false;
+}
+
+int main(int argc, char* argv[]) {
+    uint16_t port = 8080;
+
+    for (int i = 1; i < argc; ++i) {
+        std::string arg = argv[i];
+        if ((arg == "--port" || arg == "-p") && i + 1 < argc) {
+            port = static_cast<uint16_t>(std::stoi(argv[++i]));
+        }
+    }
+
+    std::signal(SIGINT, signal_handler);
+    std::signal(SIGTERM, signal_handler);
+
+    spdlog::info("DMF Studio Engine starting on port {}", port);
+
+    dmf_engine::Graph graph;
+    dmf_engine::FlowManager flow_manager;
+    dmf_engine::ProcessManager process_manager;
+
+    dmf_engine::ApiServer api_server(port, graph, flow_manager, process_manager);
+
+    spdlog::info("DMF Studio Engine ready");
+
+    while (g_running) {
+        api_server.poll(100);
+    }
+
+    spdlog::info("DMF Studio Engine shutting down");
+    return 0;
+}
diff --git a/extern/mxl b/extern/mxl
new file mode 120000
index 0000000..90d5445
--- /dev/null
+++ b/extern/mxl
@@ -0,0 +1 @@
+/home/itten/DMF/mxl
\ No newline at end of file
diff --git a/libs/dmf-engine/CMakeLists.txt b/libs/dmf-engine/CMakeLists.txt
new file mode 100644
index 0000000..c88690e
--- /dev/null
+++ b/libs/dmf-engine/CMakeLists.txt
@@ -0,0 +1,18 @@
+add_library(dmf-engine STATIC
+    src/graph.cpp
+    src/flow_manager.cpp
+    src/process_manager.cpp
+    src/api_server.cpp
+)
+
+target_include_directories(dmf-engine PUBLIC
+    include
+)
+
+target_link_libraries(dmf-engine PUBLIC
+    dmf-node
+    nlohmann_json::nlohmann_json
+    spdlog::spdlog
+    fmt::fmt
+    websockets
+)
diff --git a/libs/dmf-engine/include/dmf-engine/api_server.hpp b/libs/dmf-engine/include/dmf-engine/api_server.hpp
new file mode 100644
index 0000000..1ae6e88
--- /dev/null
+++ b/libs/dmf-engine/include/dmf-engine/api_server.hpp
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <dmf-engine/graph.hpp>
+
+#include <functional>
+#include <memory>
+#include <string>
+
+struct lws_context;
+
+namespace dmf_engine {
+
+using RequestHandler = std::function<std::string(const std::string& method, const std::string& path, const std::string& body)>;
+
+class ApiServer {
+public:
+    ApiServer(uint16_t port, Graph& graph, class FlowManager& flow_manager, class ProcessManager& process_manager);
+    ~ApiServer();
+
+    ApiServer(const ApiServer&) = delete;
+    ApiServer& operator=(const ApiServer&) = delete;
+
+    void poll(int timeout_ms);
+
+private:
+    void handle_rest(const std::string& method, const std::string& path, const std::string& body,
+                     std::string& response_status, std::string& response_content_type, std::string& response_body);
+
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
+};
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/include/dmf-engine/flow_manager.hpp b/libs/dmf-engine/include/dmf-engine/flow_manager.hpp
new file mode 100644
index 0000000..e29a998
--- /dev/null
+++ b/libs/dmf-engine/include/dmf-engine/flow_manager.hpp
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <dmf-engine/types.hpp>
+
+#include <nlohmann/json.hpp>
+
+#include <string>
+
+namespace dmf_engine {
+
+class FlowManager {
+public:
+    FlowManager();
+
+    FlowId create_flow_id();
+    nlohmann::json create_v210_flow_def(const FlowId& flow_id, int width, int height, int fps_numerator, int fps_denominator) const;
+
+private:
+    int flow_counter_ = 0;
+};
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/include/dmf-engine/graph.hpp b/libs/dmf-engine/include/dmf-engine/graph.hpp
new file mode 100644
index 0000000..d88b068
--- /dev/null
+++ b/libs/dmf-engine/include/dmf-engine/graph.hpp
@@ -0,0 +1,62 @@
+#pragma once
+
+#include <dmf-engine/types.hpp>
+
+#include <nlohmann/json.hpp>
+
+#include <optional>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace dmf_engine {
+
+enum class NodeState {
+    Stopped,
+    Starting,
+    Running,
+    Stopping,
+};
+
+struct GraphNode {
+    NodeId id;
+    std::string type;
+    nlohmann::json config;
+    NodeState state = NodeState::Stopped;
+    uint16_t control_port = 0;
+    int pid = 0;
+};
+
+struct GraphEdge {
+    EdgeId id;
+    NodeId from_node;
+    PortId from_port;
+    NodeId to_node;
+    PortId to_port;
+    FlowId flow_id;
+    nlohmann::json flow_def;
+};
+
+class Graph {
+public:
+    NodeId add_node(const std::string& type, const nlohmann::json& config = {});
+    bool remove_node(const NodeId& node_id);
+    const GraphNode* get_node(const NodeId& node_id) const;
+    std::vector<GraphNode> get_nodes() const;
+
+    EdgeId add_edge(const NodeId& from_node, const PortId& from_port,
+                    const NodeId& to_node, const PortId& to_port,
+                    const FlowId& flow_id, const nlohmann::json& flow_def);
+    bool remove_edge(const EdgeId& edge_id);
+    std::vector<GraphEdge> get_edges() const;
+    std::vector<GraphEdge> get_edges_for_node(const NodeId& node_id) const;
+
+    nlohmann::json serialize() const;
+
+private:
+    std::unordered_map<NodeId, GraphNode> nodes_;
+    std::unordered_map<EdgeId, GraphEdge> edges_;
+    int next_node_num_ = 0;
+};
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/include/dmf-engine/process_manager.hpp b/libs/dmf-engine/include/dmf-engine/process_manager.hpp
new file mode 100644
index 0000000..2574a3a
--- /dev/null
+++ b/libs/dmf-engine/include/dmf-engine/process_manager.hpp
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <dmf-engine/graph.hpp>
+
+#include <string>
+#include <unordered_map>
+
+namespace dmf_engine {
+
+class ProcessManager {
+public:
+    bool start_node(GraphNode& node, const std::string& mxl_domain, uint16_t base_port);
+    bool stop_node(GraphNode& node);
+    void stop_all();
+
+    bool is_running(const NodeId& node_id) const;
+
+private:
+    std::string find_node_binary(const std::string& node_type) const;
+};
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/include/dmf-engine/types.hpp b/libs/dmf-engine/include/dmf-engine/types.hpp
new file mode 100644
index 0000000..3bec341
--- /dev/null
+++ b/libs/dmf-engine/include/dmf-engine/types.hpp
@@ -0,0 +1,13 @@
+#pragma once
+
+#include <string>
+#include <cstdint>
+
+namespace dmf_engine {
+
+using NodeId = std::string;
+using EdgeId = std::string;
+using FlowId = std::string;
+using PortId = std::string;
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/src/api_server.cpp b/libs/dmf-engine/src/api_server.cpp
new file mode 100644
index 0000000..7537a1a
--- /dev/null
+++ b/libs/dmf-engine/src/api_server.cpp
@@ -0,0 +1,223 @@
+#include <dmf-engine/api_server.hpp>
+#include <dmf-engine/graph.hpp>
+#include <dmf-engine/flow_manager.hpp>
+#include <dmf-engine/process_manager.hpp>
+
+#include <libwebsockets.h>
+
+#include <nlohmann/json.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <cstring>
+#include <string>
+
+namespace dmf_engine {
+
+struct ApiServerImpl {
+    uint16_t port = 0;
+    Graph* graph = nullptr;
+    FlowManager* flow_manager = nullptr;
+    ProcessManager* process_manager = nullptr;
+    struct lws_context* context = nullptr;
+};
+
+struct ApiServer::Impl {
+    std::unique_ptr<ApiServerImpl> data;
+};
+
+struct HttpRequest {
+    std::string method;
+    std::string path;
+    std::string body;
+    bool body_done = false;
+};
+
+static ApiServerImpl* g_impl = nullptr;
+
+static int callback_http(struct lws* wsi, enum lws_callback_reasons reason,
+                         void* user, void* in, size_t len) {
+    auto* req = static_cast<HttpRequest*>(user);
+
+    switch (reason) {
+    case LWS_CALLBACK_HTTP: {
+        new (req) HttpRequest();
+
+        if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI) > 0) {
+            req->method = "POST";
+            char buf[256] = {};
+            lws_hdr_copy(wsi, buf, sizeof(buf), WSI_TOKEN_POST_URI);
+            req->path = buf;
+        } else {
+            req->method = "GET";
+            char buf[256] = {};
+            lws_hdr_copy(wsi, buf, sizeof(buf), WSI_TOKEN_GET_URI);
+            req->path = buf;
+        }
+        break;
+    }
+    case LWS_CALLBACK_HTTP_BODY: {
+        req->body.append(static_cast<char*>(in), len);
+        break;
+    }
+    case LWS_CALLBACK_HTTP_BODY_COMPLETION: {
+        if (!g_impl || !g_impl->graph) {
+            lws_return_http_status(wsi, HTTP_STATUS_INTERNAL_SERVER_ERROR, "Server error");
+            return -1;
+        }
+
+        std::string status_str, content_type, response_body;
+
+        auto ok = [&](const nlohmann::json& j) {
+            status_str = "200 OK";
+            response_body = j.dump();
+        };
+        auto created = [&](const nlohmann::json& j) {
+            status_str = "201 Created";
+            response_body = j.dump();
+        };
+        auto error_resp = [&](int code, const std::string& msg) {
+            status_str = std::to_string(code) + " Error";
+            response_body = nlohmann::json({{"error", msg}}).dump();
+        };
+
+        content_type = "application/json";
+
+        try {
+            nlohmann::json req_body = req->body.empty() ? nlohmann::json::object() : nlohmann::json::parse(req->body);
+
+            auto& graph = *g_impl->graph;
+            auto& fm = *g_impl->flow_manager;
+            auto& pm = *g_impl->process_manager;
+
+            if (req->path == "/api/graph" && req->method == "GET") {
+                ok(graph.serialize());
+            } else if (req->path == "/api/graph/nodes" && req->method == "POST") {
+                if (!req_body.contains("type")) {
+                    error_resp(400, "Missing 'type' field");
+                } else {
+                    auto type = req_body["type"].get<std::string>();
+                    auto config = req_body.value("config", nlohmann::json::object());
+                    auto id = graph.add_node(type, config);
+                    created({{"id", id}});
+                }
+            } else if (req->path.find("/api/graph/nodes/") == 0 && req->method == "DELETE") {
+                auto node_id = req->path.substr(std::string("/api/graph/nodes/").length());
+                if (graph.remove_node(node_id)) {
+                    ok({{"deleted", node_id}});
+                } else {
+                    error_resp(404, "Node not found: " + node_id);
+                }
+            } else if (req->path == "/api/graph/edges" && req->method == "POST") {
+                if (!req_body.contains("from_node") || !req_body.contains("to_node")) {
+                    error_resp(400, "Missing from_node/to_node");
+                } else {
+                    auto from_node = req_body["from_node"].get<std::string>();
+                    auto from_port = req_body.value("from_port", "video_out");
+                    auto to_node = req_body["to_node"].get<std::string>();
+                    auto to_port = req_body.value("to_port", "video_in");
+
+                    auto flow_id = fm.create_flow_id();
+                    auto flow_def = fm.create_v210_flow_def(flow_id, 1920, 1080, 50, 1);
+
+                    auto edge_id = graph.add_edge(from_node, from_port, to_node, to_port, flow_id, flow_def);
+                    created({{"id", edge_id}, {"flow_id", flow_id}});
+                }
+            } else if (req->path.find("/api/graph/edges/") == 0 && req->method == "DELETE") {
+                auto edge_id = req->path.substr(std::string("/api/graph/edges/").length());
+                if (graph.remove_edge(edge_id)) {
+                    ok({{"deleted", edge_id}});
+                } else {
+                    error_resp(404, "Edge not found: " + edge_id);
+                }
+            } else if (req->path == "/api/graph/start" && req->method == "POST") {
+                auto nodes = graph.get_nodes();
+                uint16_t port = 9100;
+                for (auto& node : nodes) {
+                    pm.start_node(const_cast<GraphNode&>(node), "/dev/shm/mxl", port++);
+                }
+                ok({{"status", "started"}});
+            } else if (req->path == "/api/graph/stop" && req->method == "POST") {
+                auto nodes = graph.get_nodes();
+                for (auto& node : nodes) {
+                    pm.stop_node(const_cast<GraphNode&>(node));
+                }
+                ok({{"status", "stopped"}});
+            } else {
+                error_resp(404, "Not found: " + req->method + " " + req->path);
+            }
+        } catch (const nlohmann::json::exception& e) {
+            error_resp(400, std::string("JSON error: ") + e.what());
+        } catch (const std::exception& e) {
+            error_resp(500, e.what());
+        }
+
+        auto headers = "HTTP/1.1 " + status_str + "\r\n"
+                       "Content-Type: " + content_type + "\r\n"
+                       "Access-Control-Allow-Origin: *\r\n"
+                       "Access-Control-Allow-Methods: GET, POST, DELETE, PUT, OPTIONS\r\n"
+                       "Access-Control-Allow-Headers: Content-Type\r\n"
+                       "Content-Length: " + std::to_string(response_body.size()) + "\r\n"
+                       "\r\n";
+
+        std::vector<uint8_t> buf(LWS_PRE + headers.size() + response_body.size());
+        std::memcpy(buf.data() + LWS_PRE, headers.data(), headers.size());
+        std::memcpy(buf.data() + LWS_PRE + headers.size(), response_body.data(), response_body.size());
+
+        lws_write(wsi, buf.data() + LWS_PRE, headers.size() + response_body.size(), LWS_WRITE_HTTP);
+
+        if (lws_http_transaction_completed(wsi)) {
+            return -1;
+        }
+        return 0;
+    }
+    default:
+        break;
+    }
+    return 0;
+}
+
+static const struct lws_protocols protocols[] = {
+    {"http-api", callback_http, sizeof(HttpRequest), 0},
+    {nullptr, nullptr, 0, 0},
+};
+
+ApiServer::ApiServer(uint16_t port, Graph& graph, FlowManager& flow_manager, ProcessManager& process_manager)
+    : impl_(std::make_unique<Impl>()) {
+    impl_->data = std::make_unique<ApiServerImpl>();
+    impl_->data->port = port;
+    impl_->data->graph = &graph;
+    impl_->data->flow_manager = &flow_manager;
+    impl_->data->process_manager = &process_manager;
+
+    g_impl = impl_->data.get();
+
+    struct lws_context_creation_info info;
+    std::memset(&info, 0, sizeof(info));
+    info.port = port;
+    info.protocols = protocols;
+    info.gid = -1;
+    info.uid = -1;
+
+    impl_->data->context = lws_create_context(&info);
+    if (!impl_->data->context) {
+        spdlog::error("Failed to create HTTP context on port {}", port);
+        throw std::runtime_error("Failed to create HTTP context");
+    }
+    spdlog::info("API server: listening on port {}", port);
+}
+
+ApiServer::~ApiServer() {
+    if (impl_->data && impl_->data->context) {
+        lws_context_destroy(impl_->data->context);
+    }
+    if (g_impl == impl_->data.get()) {
+        g_impl = nullptr;
+    }
+}
+
+void ApiServer::poll(int timeout_ms) {
+    lws_service(impl_->data->context, timeout_ms);
+}
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/src/flow_manager.cpp b/libs/dmf-engine/src/flow_manager.cpp
new file mode 100644
index 0000000..a89acb6
--- /dev/null
+++ b/libs/dmf-engine/src/flow_manager.cpp
@@ -0,0 +1,48 @@
+#include <dmf-engine/flow_manager.hpp>
+
+#include <nlohmann/json.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <random>
+#include <sstream>
+
+namespace dmf_engine {
+
+FlowManager::FlowManager() {
+    std::random_device rd;
+    flow_counter_ = static_cast<int>(rd());
+}
+
+FlowId FlowManager::create_flow_id() {
+    std::stringstream ss;
+    ss << std::hex << (++flow_counter_);
+    auto id = ss.str();
+    while (id.length() < 8) {
+        id = "0" + id;
+    }
+    spdlog::info("FlowManager: created flow ID: {}", id);
+    return id;
+}
+
+nlohmann::json FlowManager::create_v210_flow_def(const FlowId& flow_id, int width, int height, int fps_numerator, int fps_denominator) const {
+    auto grain_size = (width * 2) * height;
+
+    nlohmann::json flow_def;
+    flow_def["id"] = flow_id;
+    flow_def["version"] = "v1.0";
+    flow_def["label"] = "DMF Studio Flow " + flow_id;
+    flow_def["description"] = "Auto-generated V210 flow";
+    flow_def["grain_rate"] = {{"numerator", fps_numerator}, {"denominator", fps_denominator}};
+    flow_def["format"] = "video/v210";
+    flow_def["width"] = width;
+    flow_def["height"] = height;
+    flow_def["grain_size"] = grain_size;
+    flow_def["components"] = nlohmann::json::array();
+    flow_def["tags"] = nlohmann::json::object();
+    flow_def["tags"]["grouphint"] = nlohmann::json::array({"DMF Studio:Video"});
+
+    return flow_def;
+}
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/src/graph.cpp b/libs/dmf-engine/src/graph.cpp
new file mode 100644
index 0000000..f1ca009
--- /dev/null
+++ b/libs/dmf-engine/src/graph.cpp
@@ -0,0 +1,135 @@
+#include <dmf-engine/graph.hpp>
+
+#include <nlohmann/json.hpp>
+
+#include <spdlog/spdlog.h>
+
+namespace dmf_engine {
+
+NodeId Graph::add_node(const std::string& type, const nlohmann::json& config) {
+    auto id = type + "_" + std::to_string(next_node_num_++);
+    GraphNode node;
+    node.id = id;
+    node.type = type;
+    node.config = config;
+    node.state = NodeState::Stopped;
+    nodes_[id] = std::move(node);
+    spdlog::info("Graph: added node '{}' type='{}'", id, type);
+    return id;
+}
+
+bool Graph::remove_node(const NodeId& node_id) {
+    auto it = nodes_.find(node_id);
+    if (it == nodes_.end()) {
+        spdlog::warn("Graph: node '{}' not found", node_id);
+        return false;
+    }
+
+    std::vector<EdgeId> edges_to_remove;
+    for (const auto& [eid, edge] : edges_) {
+        if (edge.from_node == node_id || edge.to_node == node_id) {
+            edges_to_remove.push_back(eid);
+        }
+    }
+    for (const auto& eid : edges_to_remove) {
+        edges_.erase(eid);
+        spdlog::info("Graph: removed edge '{}' (connected to removed node '{}')", eid, node_id);
+    }
+
+    nodes_.erase(it);
+    spdlog::info("Graph: removed node '{}'", node_id);
+    return true;
+}
+
+const GraphNode* Graph::get_node(const NodeId& node_id) const {
+    auto it = nodes_.find(node_id);
+    return it != nodes_.end() ? &it->second : nullptr;
+}
+
+std::vector<GraphNode> Graph::get_nodes() const {
+    std::vector<GraphNode> result;
+    for (const auto& [_, node] : nodes_) {
+        result.push_back(node);
+    }
+    return result;
+}
+
+EdgeId Graph::add_edge(const NodeId& from_node, const PortId& from_port,
+                       const NodeId& to_node, const PortId& to_port,
+                       const FlowId& flow_id, const nlohmann::json& flow_def) {
+    auto id = from_node + ":" + from_port + "->" + to_node + ":" + to_port;
+    GraphEdge edge;
+    edge.id = id;
+    edge.from_node = from_node;
+    edge.from_port = from_port;
+    edge.to_node = to_node;
+    edge.to_port = to_port;
+    edge.flow_id = flow_id;
+    edge.flow_def = flow_def;
+    edges_[id] = std::move(edge);
+    spdlog::info("Graph: added edge '{}' flow_id={}", id, flow_id);
+    return id;
+}
+
+bool Graph::remove_edge(const EdgeId& edge_id) {
+    auto it = edges_.find(edge_id);
+    if (it == edges_.end()) {
+        spdlog::warn("Graph: edge '{}' not found", edge_id);
+        return false;
+    }
+    edges_.erase(it);
+    spdlog::info("Graph: removed edge '{}'", edge_id);
+    return true;
+}
+
+std::vector<GraphEdge> Graph::get_edges() const {
+    std::vector<GraphEdge> result;
+    for (const auto& [_, edge] : edges_) {
+        result.push_back(edge);
+    }
+    return result;
+}
+
+std::vector<GraphEdge> Graph::get_edges_for_node(const NodeId& node_id) const {
+    std::vector<GraphEdge> result;
+    for (const auto& [_, edge] : edges_) {
+        if (edge.from_node == node_id || edge.to_node == node_id) {
+            result.push_back(edge);
+        }
+    }
+    return result;
+}
+
+nlohmann::json Graph::serialize() const {
+    auto j = nlohmann::json::object();
+
+    auto nodes_arr = nlohmann::json::array();
+    for (const auto& [id, node] : nodes_) {
+        nodes_arr.push_back({
+            {"id", node.id},
+            {"type", node.type},
+            {"config", node.config},
+            {"state", static_cast<int>(node.state)},
+            {"control_port", node.control_port},
+            {"pid", node.pid},
+        });
+    }
+    j["nodes"] = nodes_arr;
+
+    auto edges_arr = nlohmann::json::array();
+    for (const auto& [id, edge] : edges_) {
+        edges_arr.push_back({
+            {"id", edge.id},
+            {"from_node", edge.from_node},
+            {"from_port", edge.from_port},
+            {"to_node", edge.to_node},
+            {"to_port", edge.to_port},
+            {"flow_id", edge.flow_id},
+        });
+    }
+    j["edges"] = edges_arr;
+
+    return j;
+}
+
+} // namespace dmf_engine
diff --git a/libs/dmf-engine/src/process_manager.cpp b/libs/dmf-engine/src/process_manager.cpp
new file mode 100644
index 0000000..376ae94
--- /dev/null
+++ b/libs/dmf-engine/src/process_manager.cpp
@@ -0,0 +1,97 @@
+#include <dmf-engine/process_manager.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <cstdlib>
+#include <filesystem>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+namespace dmf_engine {
+
+std::string ProcessManager::find_node_binary(const std::string& node_type) const {
+    std::string binary_name = "dmf-node-" + node_type;
+
+    if (const char* env_path = std::getenv("DMF_NODE_PATH")) {
+        auto candidate = std::filesystem::path(env_path) / binary_name;
+        if (std::filesystem::exists(candidate)) {
+            return candidate.string();
+        }
+    }
+
+    if (const char* self_dir_env = std::getenv("DMF_STUDIO_BIN_DIR")) {
+        auto candidate = std::filesystem::path(self_dir_env) / binary_name;
+        if (std::filesystem::exists(candidate)) {
+            return candidate.string();
+        }
+    }
+
+    return binary_name;
+}
+
+bool ProcessManager::start_node(GraphNode& node, const std::string& mxl_domain, uint16_t base_port) {
+    if (node.state == NodeState::Running) {
+        spdlog::warn("ProcessManager: node '{}' is already running", node.id);
+        return true;
+    }
+
+    auto binary = find_node_binary(node.type);
+    node.control_port = base_port;
+
+    pid_t pid = fork();
+    if (pid < 0) {
+        spdlog::error("ProcessManager: fork() failed for node '{}': {}", node.id, strerror(errno));
+        return false;
+    }
+
+    if (pid == 0) {
+        std::string port_str = std::to_string(node.control_port);
+        std::string config_str = node.config.dump();
+
+        execlp(binary.c_str(), binary.c_str(),
+               "--node-id", node.id.c_str(),
+               "--control-port", port_str.c_str(),
+               "--mxl-domain", mxl_domain.c_str(),
+               "--config", config_str.c_str(),
+               nullptr);
+
+        spdlog::error("ProcessManager: execlp failed for '{}': {}", binary, strerror(errno));
+        _exit(1);
+    }
+
+    node.pid = pid;
+    node.state = NodeState::Running;
+    spdlog::info("ProcessManager: started node '{}' pid={} port={}", node.id, pid, node.control_port);
+    return true;
+}
+
+bool ProcessManager::stop_node(GraphNode& node) {
+    if (node.state != NodeState::Running || node.pid <= 0) {
+        spdlog::warn("ProcessManager: node '{}' is not running", node.id);
+        return true;
+    }
+
+    if (kill(node.pid, SIGTERM) != 0) {
+        spdlog::error("ProcessManager: failed to send SIGTERM to node '{}': {}", node.id, strerror(errno));
+        return false;
+    }
+
+    int status = 0;
+    waitpid(node.pid, &status, 0);
+
+    spdlog::info("ProcessManager: stopped node '{}' pid={}", node.id, node.pid);
+    node.pid = 0;
+    node.state = NodeState::Stopped;
+    return true;
+}
+
+void ProcessManager::stop_all() {
+}
+
+bool ProcessManager::is_running(const NodeId& node_id) const {
+    return false;
+}
+
+} // namespace dmf_engine
diff --git a/libs/dmf-node/CMakeLists.txt b/libs/dmf-node/CMakeLists.txt
new file mode 100644
index 0000000..70d89b4
--- /dev/null
+++ b/libs/dmf-node/CMakeLists.txt
@@ -0,0 +1,17 @@
+add_library(dmf-node STATIC
+    src/control_server.cpp
+    src/node_runner.cpp
+)
+
+target_include_directories(dmf-node PUBLIC
+    include
+    ${CMAKE_SOURCE_DIR}/extern/mxl/lib/include
+)
+
+target_link_libraries(dmf-node PUBLIC
+    mxl
+    nlohmann_json::nlohmann_json
+    spdlog::spdlog
+    fmt::fmt
+    websockets
+)
diff --git a/libs/dmf-node/include/dmf-node/control_server.hpp b/libs/dmf-node/include/dmf-node/control_server.hpp
new file mode 100644
index 0000000..146423d
--- /dev/null
+++ b/libs/dmf-node/include/dmf-node/control_server.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include <dmf-node/node.hpp>
+
+#include <functional>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+struct lws;
+
+namespace dmf_node {
+
+using CommandHandler = std::function<void(const nlohmann::json& payload)>;
+using StatusCallback = std::function<void(const nlohmann::json& event)>;
+
+class ControlServer {
+public:
+    ControlServer(uint16_t port, StatusCallback on_event);
+    ~ControlServer();
+
+    ControlServer(const ControlServer&) = delete;
+    ControlServer& operator=(const ControlServer&) = delete;
+
+    void register_command(const std::string& cmd, CommandHandler handler);
+    void send_event(const nlohmann::json& event);
+
+    void poll(int timeout_ms);
+
+private:
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
+};
+
+} // namespace dmf_node
diff --git a/libs/dmf-node/include/dmf-node/node.hpp b/libs/dmf-node/include/dmf-node/node.hpp
new file mode 100644
index 0000000..52a9871
--- /dev/null
+++ b/libs/dmf-node/include/dmf-node/node.hpp
@@ -0,0 +1,32 @@
+#pragma once
+
+#include <dmf-node/port.hpp>
+#include <dmf-node/types.hpp>
+
+#include <mxl/flow.h>
+#include <mxl/mxl.h>
+
+#include <nlohmann/json.hpp>
+
+#include <memory>
+#include <vector>
+
+namespace dmf_node {
+
+class Node {
+public:
+    virtual ~Node() = default;
+
+    virtual std::string type() const = 0;
+    virtual std::vector<PortDef> input_ports() const = 0;
+    virtual std::vector<PortDef> output_ports() const = 0;
+    virtual void configure(const nlohmann::json& params) = 0;
+    virtual void on_add_writer(const std::string& port_id, mxlFlowWriter writer) = 0;
+    virtual void on_add_reader(const std::string& port_id, mxlFlowReader reader) = 0;
+    virtual void on_remove_writer(const std::string& port_id) = 0;
+    virtual void on_remove_reader(const std::string& port_id) = 0;
+    virtual void process() = 0;
+    virtual nlohmann::json status() const = 0;
+};
+
+} // namespace dmf_node
diff --git a/libs/dmf-node/include/dmf-node/node_runner.hpp b/libs/dmf-node/include/dmf-node/node_runner.hpp
new file mode 100644
index 0000000..5893824
--- /dev/null
+++ b/libs/dmf-node/include/dmf-node/node_runner.hpp
@@ -0,0 +1,39 @@
+#pragma once
+
+#include <dmf-node/node.hpp>
+#include <dmf-node/control_server.hpp>
+
+#include <mxl/mxl.h>
+
+#include <atomic>
+#include <memory>
+#include <string>
+
+namespace dmf_node {
+
+class NodeRunner {
+public:
+    template <typename NodeType>
+    static int run(int argc, char* argv[]) {
+        NodeRunner runner;
+        if (!runner.parse_args(argc, argv)) {
+            return 1;
+        }
+        auto node = std::make_unique<NodeType>();
+        return runner.exec(std::move(node));
+    }
+
+private:
+    bool parse_args(int argc, char* argv[]);
+    int exec(std::unique_ptr<Node> node);
+
+    std::string node_id_;
+    uint16_t control_port_ = 0;
+    std::string mxl_domain_ = "/dev/shm/mxl";
+    std::string config_str_;
+
+    mxlInstance mxl_instance_ = nullptr;
+    std::atomic<bool> running_{false};
+};
+
+} // namespace dmf_node
diff --git a/libs/dmf-node/include/dmf-node/port.hpp b/libs/dmf-node/include/dmf-node/port.hpp
new file mode 100644
index 0000000..1bcb805
--- /dev/null
+++ b/libs/dmf-node/include/dmf-node/port.hpp
@@ -0,0 +1,25 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+namespace dmf_node {
+
+enum class MediaType : uint8_t {
+    VideoV210,
+    AudioFloat32,
+    AncData,
+};
+
+enum class PortDirection : uint8_t {
+    Input,
+    Output,
+};
+
+struct PortDef {
+    std::string id;
+    PortDirection direction;
+    MediaType media_type;
+};
+
+} // namespace dmf_node
diff --git a/libs/dmf-node/include/dmf-node/types.hpp b/libs/dmf-node/include/dmf-node/types.hpp
new file mode 100644
index 0000000..6228b8b
--- /dev/null
+++ b/libs/dmf-node/include/dmf-node/types.hpp
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <string>
+
+namespace dmf_node {
+
+using NodeId = std::string;
+using PortId = std::string;
+using FlowId = std::string;
+
+} // namespace dmf_node
diff --git a/libs/dmf-node/src/control_server.cpp b/libs/dmf-node/src/control_server.cpp
new file mode 100644
index 0000000..61c268a
--- /dev/null
+++ b/libs/dmf-node/src/control_server.cpp
@@ -0,0 +1,169 @@
+#include <dmf-node/control_server.hpp>
+#include <dmf-node/node.hpp>
+
+#include <libwebsockets.h>
+
+#include <nlohmann/json.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <cstring>
+#include <mutex>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace dmf_node {
+
+struct ControlServerData {
+    StatusCallback on_event;
+    std::unordered_map<std::string, CommandHandler> commands;
+    std::mutex send_mutex;
+    std::vector<std::string> send_queue;
+    struct lws* client_wsi = nullptr;
+};
+
+struct ControlServer::Impl {
+    uint16_t port;
+    std::unique_ptr<ControlServerData> data;
+    struct lws_context* context = nullptr;
+};
+
+static int callback_ws(struct lws* wsi, enum lws_callback_reasons reason,
+                       void* user, void* in, size_t len);
+
+static const struct lws_protocols protocols[] = {
+    {
+        "dmf-control",
+        callback_ws,
+        sizeof(ControlServerData*),
+        65536,
+    },
+    {nullptr, nullptr, 0, 0},
+};
+
+static int callback_ws(struct lws* wsi, enum lws_callback_reasons reason,
+                       void* user, void* in, size_t len) {
+    auto** ppdata = static_cast<ControlServerData**>(user);
+    ControlServerData* data = ppdata ? *ppdata : nullptr;
+
+    switch (reason) {
+    case LWS_CALLBACK_ESTABLISHED: {
+        auto* vhost = lws_get_vhost(wsi);
+        data = static_cast<ControlServerData*>(lws_vhost_user(vhost));
+        if (ppdata) {
+            *ppdata = data;
+        }
+        if (data) {
+            data->client_wsi = wsi;
+        }
+        spdlog::info("Control WS: client connected");
+        break;
+    }
+    case LWS_CALLBACK_RECEIVE: {
+        if (!data) {
+            auto* vhost = lws_get_vhost(wsi);
+            data = static_cast<ControlServerData*>(lws_vhost_user(vhost));
+        }
+        if (!data) {
+            break;
+        }
+
+        try {
+            auto msg = nlohmann::json::parse(static_cast<char*>(in), static_cast<char*>(in) + len);
+            if (!msg.contains("cmd")) {
+                spdlog::warn("Control WS: message missing 'cmd' field");
+                break;
+            }
+            auto cmd = msg["cmd"].get<std::string>();
+            auto it = data->commands.find(cmd);
+            if (it != data->commands.end()) {
+                it->second(msg);
+            } else {
+                spdlog::warn("Control WS: unknown command '{}'", cmd);
+            }
+        } catch (const nlohmann::json::parse_error& e) {
+            spdlog::warn("Control WS: JSON parse error: {}", e.what());
+        }
+        break;
+    }
+    case LWS_CALLBACK_SERVER_WRITEABLE: {
+        if (!data) {
+            auto* vhost = lws_get_vhost(wsi);
+            data = static_cast<ControlServerData*>(lws_vhost_user(vhost));
+        }
+        if (!data) {
+            break;
+        }
+
+        std::lock_guard<std::mutex> lock(data->send_mutex);
+        while (!data->send_queue.empty()) {
+            auto& msg = data->send_queue.back();
+            std::vector<uint8_t> buf(LWS_PRE + msg.size());
+            std::memcpy(buf.data() + LWS_PRE, msg.data(), msg.size());
+            lws_write(wsi, buf.data() + LWS_PRE, msg.size(), LWS_WRITE_TEXT);
+            data->send_queue.pop_back();
+        }
+        break;
+    }
+    case LWS_CALLBACK_CLOSED: {
+        if (data) {
+            data->client_wsi = nullptr;
+        }
+        spdlog::info("Control WS: client disconnected");
+        break;
+    }
+    default:
+        break;
+    }
+    return 0;
+}
+
+ControlServer::ControlServer(uint16_t port, StatusCallback on_event)
+    : impl_(std::make_unique<Impl>()) {
+    impl_->port = port;
+    impl_->data = std::make_unique<ControlServerData>();
+    impl_->data->on_event = std::move(on_event);
+
+    struct lws_context_creation_info info;
+    std::memset(&info, 0, sizeof(info));
+    info.port = port;
+    info.protocols = protocols;
+    info.user = impl_->data.get();
+    info.gid = -1;
+    info.uid = -1;
+
+    impl_->context = lws_create_context(&info);
+    if (!impl_->context) {
+        spdlog::error("Failed to create WS context on port {}", port);
+        throw std::runtime_error("Failed to create WS context");
+    }
+    spdlog::info("Control WS: listening on port {}", port);
+}
+
+ControlServer::~ControlServer() {
+    if (impl_->context) {
+        lws_context_destroy(impl_->context);
+    }
+}
+
+void ControlServer::register_command(const std::string& cmd, CommandHandler handler) {
+    impl_->data->commands[cmd] = std::move(handler);
+}
+
+void ControlServer::send_event(const nlohmann::json& event) {
+    auto data = event.dump();
+    {
+        std::lock_guard<std::mutex> lock(impl_->data->send_mutex);
+        impl_->data->send_queue.push_back(data);
+    }
+    if (impl_->data->client_wsi) {
+        lws_callback_on_writable(impl_->data->client_wsi);
+    }
+}
+
+void ControlServer::poll(int timeout_ms) {
+    lws_service(impl_->context, timeout_ms);
+}
+
+} // namespace dmf_node
diff --git a/libs/dmf-node/src/node_runner.cpp b/libs/dmf-node/src/node_runner.cpp
new file mode 100644
index 0000000..266e04c
--- /dev/null
+++ b/libs/dmf-node/src/node_runner.cpp
@@ -0,0 +1,184 @@
+#include <dmf-node/node_runner.hpp>
+#include <dmf-node/control_server.hpp>
+
+#include <mxl/flow.h>
+#include <mxl/mxl.h>
+
+#include <nlohmann/json.hpp>
+
+#include <spdlog/spdlog.h>
+
+#include <cstring>
+#include <csignal>
+#include <filesystem>
+#include <thread>
+
+namespace dmf_node {
+
+static std::atomic<bool> g_running{true};
+
+static void signal_handler(int /*signum*/) {
+    g_running = false;
+}
+
+bool NodeRunner::parse_args(int argc, char* argv[]) {
+    for (int i = 1; i < argc; ++i) {
+        std::string arg = argv[i];
+        if ((arg == "--node-id" || arg == "-n") && i + 1 < argc) {
+            node_id_ = argv[++i];
+        } else if ((arg == "--control-port" || arg == "-p") && i + 1 < argc) {
+            control_port_ = static_cast<uint16_t>(std::stoi(argv[++i]));
+        } else if ((arg == "--mxl-domain" || arg == "-d") && i + 1 < argc) {
+            mxl_domain_ = argv[++i];
+        } else if ((arg == "--config" || arg == "-c") && i + 1 < argc) {
+            config_str_ = argv[++i];
+        } else if (arg == "--help" || arg == "-h") {
+            spdlog::info("Usage: {} [options]", argv[0]);
+            spdlog::info("  --node-id, -n       Node instance ID");
+            spdlog::info("  --control-port, -p  WebSocket control port");
+            spdlog::info("  --mxl-domain, -d    MXL domain path (default: /dev/shm/mxl)");
+            spdlog::info("  --config, -c        Node configuration JSON");
+            return false;
+        }
+    }
+
+    if (node_id_.empty()) {
+        spdlog::error("--node-id is required");
+        return false;
+    }
+    if (control_port_ == 0) {
+        spdlog::error("--control-port is required");
+        return false;
+    }
+    return true;
+}
+
+int NodeRunner::exec(std::unique_ptr<Node> node) {
+    std::signal(SIGINT, signal_handler);
+    std::signal(SIGTERM, signal_handler);
+
+    spdlog::info("Starting node '{}' type='{}'", node_id_, node->type());
+
+    if (!std::filesystem::exists(mxl_domain_)) {
+        spdlog::error("MXL domain path does not exist: {}", mxl_domain_);
+        return 1;
+    }
+
+    mxl_instance_ = mxlCreateInstance(mxl_domain_.c_str(), nullptr);
+    if (!mxl_instance_) {
+        spdlog::error("Failed to create MXL instance on domain: {}", mxl_domain_);
+        return 1;
+    }
+    spdlog::info("MXL instance created on domain: {}", mxl_domain_);
+
+    mxlGarbageCollectFlows(mxl_instance_);
+
+    if (!config_str_.empty()) {
+        try {
+            auto cfg = nlohmann::json::parse(config_str_);
+            node->configure(cfg);
+        } catch (const nlohmann::json::parse_error& e) {
+            spdlog::error("Failed to parse config JSON: {}", e.what());
+            mxlDestroyInstance(mxl_instance_);
+            return 1;
+        }
+    }
+
+    auto control_server = std::make_unique<ControlServer>(control_port_, [](const nlohmann::json& /*event*/) {});
+
+    auto mk_ports = [](const std::vector<PortDef>& ports) {
+        auto arr = nlohmann::json::array();
+        for (const auto& p : ports) {
+            arr.push_back({{"id", p.id}, {"direction", p.direction == PortDirection::Input ? "input" : "output"}, {"media_type", static_cast<int>(p.media_type)}});
+        }
+        return arr;
+    };
+
+    control_server->register_command("add_writer", [&, w = std::unordered_map<std::string, mxlFlowWriter>{}](const nlohmann::json& msg) mutable {
+        auto flow_id = msg["flow_id"].get<std::string>();
+        auto port_id = msg["port_id"].get<std::string>();
+        auto flow_def = msg["flow_def"].dump();
+
+        mxlFlowWriter writer = nullptr;
+        bool created = false;
+        mxlFlowConfigInfo config_info{};
+        auto status = mxlCreateFlowWriter(mxl_instance_, flow_def.c_str(), nullptr, &writer, &config_info, &created);
+        if (status != MXL_STATUS_OK || !writer) {
+            spdlog::error("Failed to create flow writer for flow {}: status={}", flow_id, static_cast<int>(status));
+            return;
+        }
+        spdlog::info("Created flow writer on port '{}' flow {} (created={})", port_id, flow_id, created);
+        node->on_add_writer(port_id, writer);
+    });
+
+    control_server->register_command("add_reader", [&](const nlohmann::json& msg) {
+        auto flow_id = msg["flow_id"].get<std::string>();
+        auto port_id = msg["port_id"].get<std::string>();
+
+        mxlFlowReader reader = nullptr;
+        auto status = mxlCreateFlowReader(mxl_instance_, flow_id.c_str(), nullptr, &reader);
+        if (status != MXL_STATUS_OK || !reader) {
+            spdlog::error("Failed to create flow reader for flow {}: status={}", flow_id, static_cast<int>(status));
+            return;
+        }
+        spdlog::info("Created flow reader on port '{}' flow {}", port_id, flow_id);
+        node->on_add_reader(port_id, reader);
+    });
+
+    control_server->register_command("remove_writer", [&](const nlohmann::json& msg) {
+        auto port_id = msg["port_id"].get<std::string>();
+        node->on_remove_writer(port_id);
+        spdlog::info("Removed writer on port '{}'", port_id);
+    });
+
+    control_server->register_command("remove_reader", [&](const nlohmann::json& msg) {
+        auto port_id = msg["port_id"].get<std::string>();
+        node->on_remove_reader(port_id);
+        spdlog::info("Removed reader on port '{}'", port_id);
+    });
+
+    control_server->register_command("configure", [&](const nlohmann::json& msg) {
+        if (msg.contains("params")) {
+            node->configure(msg["params"]);
+            spdlog::info("Reconfigured node '{}'", node_id_);
+        }
+    });
+
+    control_server->register_command("shutdown", [&](const nlohmann::json& /*msg*/) {
+        spdlog::info("Shutdown command received");
+        g_running = false;
+    });
+
+    nlohmann::json ready_event;
+    ready_event["event"] = "ready";
+    ready_event["type"] = node->type();
+    ready_event["node_id"] = node_id_;
+    ready_event["ports"] = mk_ports(node->input_ports());
+    for (const auto& p : node->output_ports()) {
+        ready_event["ports"].push_back({{"id", p.id}, {"direction", "output"}, {"media_type", static_cast<int>(p.media_type)}});
+    }
+    control_server->send_event(ready_event);
+
+    running_ = true;
+    spdlog::info("Node '{}' entering process loop", node_id_);
+
+    while (g_running && running_) {
+        control_server->poll(1);
+        node->process();
+
+        static int status_counter = 0;
+        if (++status_counter % 100 == 0) {
+            nlohmann::json status_event;
+            status_event["event"] = "status";
+            status_event["node_id"] = node_id_;
+            status_event["data"] = node->status();
+            control_server->send_event(status_event);
+        }
+    }
+
+    spdlog::info("Node '{}' shutting down", node_id_);
+    mxlDestroyInstance(mxl_instance_);
+    return 0;
+}
+
+} // namespace dmf_node
diff --git a/nodes/passthrough/CMakeLists.txt b/nodes/passthrough/CMakeLists.txt
new file mode 100644
index 0000000..5ae4c51
--- /dev/null
+++ b/nodes/passthrough/CMakeLists.txt
@@ -0,0 +1,6 @@
+add_executable(dmf-node-passthrough
+    src/main.cpp
+    src/passthrough_node.cpp
+)
+
+target_link_libraries(dmf-node-passthrough PRIVATE dmf-node)
diff --git a/nodes/passthrough/src/main.cpp b/nodes/passthrough/src/main.cpp
new file mode 100644
index 0000000..e9f1d18
--- /dev/null
+++ b/nodes/passthrough/src/main.cpp
@@ -0,0 +1,6 @@
+#include <dmf-node/node_runner.hpp>
+#include "passthrough_node.hpp"
+
+int main(int argc, char* argv[]) {
+    return dmf_node::NodeRunner::run<dmf_node::PassthroughNode>(argc, argv);
+}
diff --git a/nodes/passthrough/src/passthrough_node.cpp b/nodes/passthrough/src/passthrough_node.cpp
new file mode 100644
index 0000000..1d52bba
--- /dev/null
+++ b/nodes/passthrough/src/passthrough_node.cpp
@@ -0,0 +1,94 @@
+#include "passthrough_node.hpp"
+
+#include <mxl/flow.h>
+#include <mxl/mxl.h>
+
+#include <spdlog/spdlog.h>
+
+#include <cstring>
+
+namespace dmf_node {
+
+void PassthroughNode::on_add_writer(const std::string& port_id, mxlFlowWriter writer) {
+    if (port_id == "video_out") {
+        writer_ = writer;
+        spdlog::info("Passthrough: writer added on video_out");
+    }
+}
+
+void PassthroughNode::on_add_reader(const std::string& port_id, mxlFlowReader reader) {
+    if (port_id == "video_in") {
+        reader_ = reader;
+        spdlog::info("Passthrough: reader added on video_in");
+    }
+}
+
+void PassthroughNode::on_remove_writer(const std::string& port_id) {
+    if (port_id == "video_out") {
+        writer_.reset();
+        spdlog::info("Passthrough: writer removed from video_out");
+    }
+}
+
+void PassthroughNode::on_remove_reader(const std::string& port_id) {
+    if (port_id == "video_in") {
+        reader_.reset();
+        spdlog::info("Passthrough: reader removed from video_in");
+    }
+}
+
+void PassthroughNode::process() {
+    if (!reader_ || !writer_) {
+        return;
+    }
+
+    mxlGrainInfo grain_info{};
+    uint8_t* payload = nullptr;
+
+    auto status = mxlFlowReaderGetGrain(*reader_, read_index_, 100000000ULL, &grain_info, &payload);
+    if (status != MXL_STATUS_OK) {
+        if (status == MXL_ERR_TIMEOUT) {
+            return;
+        }
+        if (status == MXL_ERR_OUT_OF_RANGE_TOO_LATE) {
+            mxlFlowRuntimeInfo runtime{};
+            mxlFlowReaderGetRuntimeInfo(*reader_, &runtime);
+            read_index_ = runtime.headIndex;
+            return;
+        }
+        return;
+    }
+
+    mxlGrainInfo out_grain{};
+    uint8_t* out_payload = nullptr;
+    status = mxlFlowWriterOpenGrain(*writer_, write_index_, &out_grain, &out_payload);
+    if (status != MXL_STATUS_OK) {
+        spdlog::warn("Passthrough: failed to open output grain at index {}: {}", write_index_, static_cast<int>(status));
+        read_index_++;
+        return;
+    }
+
+    auto copy_size = std::min(grain_info.grainSize, out_grain.grainSize);
+    std::memcpy(out_payload, payload, copy_size);
+
+    out_grain.validSlices = grain_info.validSlices;
+    out_grain.flags = grain_info.flags;
+    mxlFlowWriterCommitGrain(*writer_, &out_grain);
+
+    read_index_++;
+    write_index_++;
+    grains_processed_++;
+}
+
+nlohmann::json PassthroughNode::status() const {
+    return {
+        {"type", "passthrough"},
+        {"grains_processed", grains_processed_},
+        {"read_index", read_index_},
+        {"write_index", write_index_},
+        {"has_reader", reader_.has_value()},
+        {"has_writer", writer_.has_value()},
+    };
+}
+
+} // namespace dmf_node
diff --git a/nodes/passthrough/src/passthrough_node.hpp b/nodes/passthrough/src/passthrough_node.hpp
new file mode 100644
index 0000000..ec4a6a4
--- /dev/null
+++ b/nodes/passthrough/src/passthrough_node.hpp
@@ -0,0 +1,45 @@
+#pragma once
+
+#include <dmf-node/node.hpp>
+
+#include <mxl/flow.h>
+
+#include <unordered_map>
+#include <optional>
+
+namespace dmf_node {
+
+class PassthroughNode : public Node {
+public:
+    PassthroughNode() = default;
+
+    std::string type() const override { return "passthrough"; }
+
+    std::vector<PortDef> input_ports() const override {
+        return {{"video_in", PortDirection::Input, MediaType::VideoV210}};
+    }
+
+    std::vector<PortDef> output_ports() const override {
+        return {{"video_out", PortDirection::Output, MediaType::VideoV210}};
+    }
+
+    void configure(const nlohmann::json& /*params*/) override {}
+
+    void on_add_writer(const std::string& port_id, mxlFlowWriter writer) override;
+    void on_add_reader(const std::string& port_id, mxlFlowReader reader) override;
+    void on_remove_writer(const std::string& port_id) override;
+    void on_remove_reader(const std::string& port_id) override;
+
+    void process() override;
+    nlohmann::json status() const override;
+
+private:
+    std::optional<mxlFlowReader> reader_;
+    std::optional<mxlFlowWriter> writer_;
+    mxlInstance mxl_instance_ = nullptr;
+    uint64_t read_index_ = 0;
+    uint64_t write_index_ = 0;
+    uint64_t grains_processed_ = 0;
+};
+
+} // namespace dmf_node
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 0000000..d02b9b6
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,8 @@
+add_executable(dmf-test-graph
+    test_graph.cpp
+)
+
+target_link_libraries(dmf-test-graph PRIVATE
+    dmf-engine
+    Catch2::Catch2WithMain
+)
diff --git a/tests/test_graph.cpp b/tests/test_graph.cpp
new file mode 100644
index 0000000..edcdbc7
--- /dev/null
+++ b/tests/test_graph.cpp
@@ -0,0 +1,88 @@
+#include <dmf-engine/graph.hpp>
+#include <dmf-engine/flow_manager.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("Graph add and remove nodes", "[graph]") {
+    dmf_engine::Graph graph;
+
+    auto id1 = graph.add_node("passthrough");
+    auto id2 = graph.add_node("test-source");
+
+    REQUIRE(graph.get_node(id1) != nullptr);
+    REQUIRE(graph.get_node(id2) != nullptr);
+    REQUIRE(graph.get_node(id1)->type == "passthrough");
+    REQUIRE(graph.get_node(id2)->type == "test-source");
+
+    auto nodes = graph.get_nodes();
+    REQUIRE(nodes.size() == 2);
+
+    graph.remove_node(id1);
+    REQUIRE(graph.get_node(id1) == nullptr);
+    REQUIRE(graph.get_nodes().size() == 1);
+}
+
+TEST_CASE("Graph add and remove edges", "[graph]") {
+    dmf_engine::Graph graph;
+
+    auto n1 = graph.add_node("test-source");
+    auto n2 = graph.add_node("passthrough");
+
+    auto edge_id = graph.add_edge(n1, "video_out", n2, "video_in", "flow1", {});
+    REQUIRE(graph.get_edges().size() == 1);
+
+    graph.remove_edge(edge_id);
+    REQUIRE(graph.get_edges().size() == 0);
+}
+
+TEST_CASE("Graph remove node also removes edges", "[graph]") {
+    dmf_engine::Graph graph;
+
+    auto n1 = graph.add_node("test-source");
+    auto n2 = graph.add_node("passthrough");
+
+    graph.add_edge(n1, "video_out", n2, "video_in", "flow1", {});
+    graph.add_edge(n2, "video_out", n1, "video_in", "flow2", {});
+
+    REQUIRE(graph.get_edges().size() == 2);
+
+    graph.remove_node(n1);
+    REQUIRE(graph.get_edges().size() == 0);
+}
+
+TEST_CASE("FlowManager creates unique IDs", "[flow_manager]") {
+    dmf_engine::FlowManager fm1;
+    dmf_engine::FlowManager fm2;
+
+    auto id1 = fm1.create_flow_id();
+    auto id2 = fm1.create_flow_id();
+    auto id3 = fm2.create_flow_id();
+
+    REQUIRE(id1 != id2);
+    REQUIRE(id2 != id3);
+}
+
+TEST_CASE("FlowManager creates V210 flow definition", "[flow_manager]") {
+    dmf_engine::FlowManager fm;
+    auto flow_id = fm.create_flow_id();
+    auto def = fm.create_v210_flow_def(flow_id, 1920, 1080, 50, 1);
+
+    REQUIRE(def["id"] == flow_id);
+    REQUIRE(def["format"] == "video/v210");
+    REQUIRE(def["width"] == 1920);
+    REQUIRE(def["height"] == 1080);
+}
+
+TEST_CASE("Graph serialize", "[graph]") {
+    dmf_engine::Graph graph;
+
+    auto n1 = graph.add_node("test-source");
+    auto n2 = graph.add_node("passthrough");
+    graph.add_edge(n1, "video_out", n2, "video_in", "flow1", {});
+
+    auto j = graph.serialize();
+    REQUIRE(j.contains("nodes"));
+    REQUIRE(j.contains("edges"));
+    REQUIRE(j["nodes"].size() == 2);
+    REQUIRE(j["edges"].size() == 1);
+}
diff --git a/vcpkg.json b/vcpkg.json
new file mode 100644
index 0000000..d12145e
--- /dev/null
+++ b/vcpkg.json
@@ -0,0 +1,20 @@
+{
+  "name": "dmf-studio",
+  "version": "0.1.0",
+  "dependencies": [
+    "libwebsockets",
+    "nlohmann-json",
+    "spdlog",
+    "fmt",
+    "catch2",
+    {
+      "name": "stduuid",
+      "version>=": "1.2.3",
+      "features": ["system-gen", "gsl-span"]
+    },
+    "picojson",
+    "cli11",
+    "ada-url"
+  ],
+  "builtin-baseline": "432412eecac55981cf608cc12e5b4bd91768ec57"
+}