diff --git a/src/citadel/mqtt/__init__.py b/src/citadel/mqtt/__init__.py
index cf5d515..ccc1346 100644
--- a/src/citadel/mqtt/__init__.py
+++ b/src/citadel/mqtt/__init__.py
@@ -6,6 +6,12 @@ from typing import NoReturn
 
 import paho.mqtt.client as mqtt
 
+class Configuration:
+    user: str
+    password: str
+    host: str
+    port: int
+
 class Client(mqtt.Client):
     def __init__(self, logger: logging.Logger=None):
         super().__init__()
@@ -15,6 +21,9 @@ class Client(mqtt.Client):
             self.logger = logging.getLogger('mqtt')
 
         self._subscribe_callbacks = []
+        self._on_connect_callbacks = []
+
+        self.on_connect = self._on_connect2
 
     def setup(self, host: str, port: int, username: str, password: str):
         self._username = username
@@ -37,18 +46,22 @@ class Client(mqtt.Client):
         self._subscribe_callbacks.append((topic,callback))
         self.message_callback_add(topic, callback)
 
-    @property
-    def on_connect(self):
-        #TODO: called twice because of a boolean check before call
+    def _on_connect2(self, *args):
         for (topic, callback) in self._subscribe_callbacks:
             self.subscribe(topic)
-        return self._on_connect
+        for func in self._on_connect_callbacks:
+            func(self, *args)
 
-    @on_connect.setter
+    def add_on_connect_callback(self, func):
+        with self._callback_mutex:
+            self._on_connect_callbacks.append(func)
+
+    @mqtt.Client.on_connect.setter
     def on_connect(self, func):
         with self._callback_mutex:
             self._on_connect = func
 
+
 class MQTTApp:
     """ Manage MQTT connection and on topic callback with help of the @topic decorator """