diff --git a/doorlockd/CMakeLists.txt b/doorlockd/CMakeLists.txt
index a1440ea..38480ae 100644
--- a/doorlockd/CMakeLists.txt
+++ b/doorlockd/CMakeLists.txt
@@ -9,6 +9,11 @@ set(DOORLOCK_VERSION_PATCH 0)
 
 set(DOORLOCK_VERSION "${DOORLOCK_VERSION_MAJOR}.${DOORLOCK_VERSION_MINOR}-${DOORLOCK_VERSION_PATCH}")
 
+# Instruct CMake to run moc automatically when needed.
+set(CMAKE_AUTOMOC ON)
+set(CMAKE_AUTOUIC ON)
+include_directories(${CMAKE_SOURCE_DIR}/src)
+
 MESSAGE(STATUS "doorlockd version: ${DOORLOCK_VERSION}")
 
 # Get the current working branch
@@ -51,6 +56,8 @@ include_directories(${JSON_INCLUDE_DIR})
 
 find_package (Threads)
 
+find_package(Qt5Widgets)
+
 set(DOORLOCKD_SRCS
     src/clientmessage.cpp
     src/clientmessage.h
@@ -80,6 +87,8 @@ set(DOORLOCK_CLIENT_SRCS
     src/response.h
     src/util.cpp
     src/util.h
+    src/qrwidget.cpp
+    src/qrwidget.h
 
     src/doorlock-client.cpp
 )
@@ -88,7 +97,8 @@ add_executable(doorlockd ${DOORLOCKD_SRCS})
 target_link_libraries(doorlockd jsoncpp ldap ${Boost_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
 
 add_executable(doorlock-client ${DOORLOCK_CLIENT_SRCS})
-target_link_libraries(doorlock-client jsoncpp ${Boost_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
+target_link_libraries(doorlock-client jsoncpp ${Boost_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
+                      qrencode Qt5::Widgets)
 
 install(TARGETS doorlockd DESTINATION sbin/)
 install(TARGETS doorlock-client DESTINATION bin/)
diff --git a/doorlockd/src/doorlock-client.cpp b/doorlockd/src/doorlock-client.cpp
index cb296d0..d307cb4 100644
--- a/doorlockd/src/doorlock-client.cpp
+++ b/doorlockd/src/doorlock-client.cpp
@@ -1,6 +1,7 @@
 #include <exception>
 #include <iostream>
 #include <string>
+#include <thread>
 
 #include <boost/asio.hpp>
 #include <boost/program_options.hpp>
@@ -10,6 +11,9 @@
 #include "logger.h"
 #include "response.h"
 
+#include <QApplication>
+#include "qrwidget.h"
+
 // Info about doorlock-client version
 const static std::string version =
         "doorlock-client-" DOORLOCK_VERSION;
@@ -29,20 +33,37 @@ const static std::string subscriptionCommand =
 // The receive buffer length of the TCP socket
 const int constexpr SOCKET_BUFFERLENGTH = 2048;
 
+static volatile bool run = true;
+
+static std::unique_ptr<QRWidget> qrWidget = nullptr;
+
 static void doorlock_update(const Clientmessage &msg)
 {
-    // TODO develop small X application to show the QR code
-    char buffer[1024];
-    snprintf(buffer, sizeof(buffer),
-             "qrencode -t ansi %s",
-             msg.token().c_str());
-    system(buffer);
+    if (qrWidget) {
+        qrWidget->setQRData(msg.token());
+    }
+}
+
+static int startGui(int argc, char** argv)
+{
+    QApplication app(argc, argv);
+
+    app.setOrganizationName("Binary Kitchen");
+    app.setApplicationName("doorlock-client");
+
+    qrWidget = std::unique_ptr<QRWidget>(new QRWidget);
+    qrWidget->showFullScreen();
+
+    int retval = app.exec();
+    run = false;
+    return retval;
 }
 
 static int doorlock_client(const std::string &hostname,
                            const unsigned short port)
 {
     int retval = 0;
+    std::thread guiThread;
 
     try {
         tcp::resolver resolver(io_service);
@@ -75,7 +96,11 @@ static int doorlock_client(const std::string &hostname,
         if (!response)
             throw std::runtime_error("Invalid response from server");
 
-        for (;;) {
+        guiThread = std::thread([] () {
+            startGui(0, nullptr);
+        });
+
+        for (;run;) {
             length = socket.read_some(boost::asio::buffer(data), error);
             if (error)
                 throw boost::system::system_error(error);
@@ -94,6 +119,9 @@ static int doorlock_client(const std::string &hostname,
     }
 
 out:
+    if (guiThread.joinable()) {
+        guiThread.join();
+    }
     return retval;
 }
 
@@ -137,7 +165,8 @@ int main(int argc, char** argv)
     }
 
     l(LogLevel::notice, "Starting doorlock-client");
-    retval = doorlock_client(hostname, port);
+
+    doorlock_client(hostname, port);
 
 out:
     l(LogLevel::notice, "Stopping doorlock-client");
diff --git a/doorlockd/src/qrwidget.cpp b/doorlockd/src/qrwidget.cpp
new file mode 100644
index 0000000..126f506
--- /dev/null
+++ b/doorlockd/src/qrwidget.cpp
@@ -0,0 +1,63 @@
+#include <exception>
+#include <memory>
+
+#include <QPainter>
+#include <QDebug>
+
+#include <qrencode.h>
+
+#include "qrwidget.h"
+
+QRWidget::QRWidget(QWidget* parent) :
+    QWidget(parent),
+    _data(" ")
+{
+}
+
+void QRWidget::setQRData(const std::string &data)
+{
+    _data = QString::fromStdString(data);
+    update();
+}
+
+void QRWidget::paintEvent(QPaintEvent*)
+{
+    QPainter painter(this);
+
+    std::unique_ptr<QRcode, void(*)(QRcode*)> qr(
+                QRcode_encodeString(_data.toStdString().c_str(), 1, QR_ECLEVEL_L, QR_MODE_8, 0),
+                [] (QRcode* ptr) {
+        if (ptr)
+            QRcode_free(ptr);
+    });
+
+    if (!qr)
+        throw std::runtime_error("Error generating QR Code");
+
+    QColor fg("black");
+    QColor bg("white");
+
+    painter.setBrush(bg);
+    painter.setPen(Qt::NoPen);
+    painter.drawRect(0,0,width(),height());
+    painter.setBrush(fg);
+
+    const int s=qr->width>0?qr->width:1;
+    const double w=width();
+    const double h=height();
+    const double aspect=w/h;
+    const double scale=((aspect>1.0)?h:w)/s;
+
+    for(int y=0;y<s;y++) {
+        const int yy=y*s;
+        for(int x=0;x<s;x++) {
+            const int xx=yy+x;
+            const unsigned char b=qr->data[xx];
+            if(b &0x01) {
+                const double rx1=x*scale, ry1=y*scale;
+                QRectF r(rx1, ry1, scale, scale);
+                painter.drawRects(&r,1);
+            }
+        }
+    }
+}
diff --git a/doorlockd/src/qrwidget.h b/doorlockd/src/qrwidget.h
new file mode 100644
index 0000000..32e6128
--- /dev/null
+++ b/doorlockd/src/qrwidget.h
@@ -0,0 +1,21 @@
+#ifndef QRWIDGET_H
+#define QRWIDGET_H
+
+#include <QWidget>
+
+class QRWidget : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit QRWidget(QWidget *parent = nullptr);
+    void setQRData(const std::string &data);
+
+private:
+    QString _data;
+
+protected:
+    void paintEvent(QPaintEvent *);
+};
+
+#endif