diff --git a/software/backend/data_handling_functions.py b/software/backend/data_handling_functions.py
index a495826..1bd1ca6 100644
--- a/software/backend/data_handling_functions.py
+++ b/software/backend/data_handling_functions.py
@@ -3,4 +3,75 @@ created by caliskan at 19.04.2023
 
 This file contains all functions, which handle the different cases.
 Every function should return json format with the wanted data from the database
-"""
\ No newline at end of file
+"""
+import paho.mqtt.client as mqtt
+
+
+def data_handler(client: mqtt.Client, message) -> dict:
+    """
+    main entrypoint for a message handling method
+    :param client:
+    :param message:
+    :return:
+    """
+    if message.topic.startwith('BackEnd'):
+
+        if message.topic == "BackEnd/Action/All":
+            action_all(client, message)
+        elif message.topic == "BackEnd/Action/GetPosition":
+            action_get_position(client, message)
+        elif message.topic == "BackEnd/Action/GetBattery":
+            action_get_battery(client, message)
+        elif message.topic == "BackEnd/Action/GetAllData":
+            action_get_all_data(client, message)
+
+    elif message.topic.startwith('Robot'):
+
+        if message.topic == "Robot/Data/SensorData":
+            data_sensordata(client, message)
+        elif message.topic == "Robot/Data/Position":
+            data_position(client, message)
+        elif message.topic == "Robot/Data/Battery":
+            data_battery(client, message)
+        elif message.topic == "Robot/Data/Picture":
+            data_picture(client, message)
+
+
+# START ACTION FUNCTION DEFINITIONS
+
+def action_all(client, message):
+    pass
+
+
+def action_get_position(client, message):
+    pass
+
+
+def action_get_battery(client, message):
+    pass
+
+
+def action_get_all_data(client, message):
+    pass
+
+
+# END ACTION FUNCTION DEFINITIONS
+
+# START ROBOT FUNCTION DEFINITIONS
+
+def data_sensordata(client, message):
+    pass
+
+
+def data_position(client, message):
+    pass
+
+
+def data_battery(client, message):
+    pass
+
+
+def data_picture(client, message):
+    pass
+
+# END ROBOT FUNCTION DEFINITIONS
diff --git a/software/backend/defines.py b/software/backend/defines.py
index 2574007..947b4d6 100644
--- a/software/backend/defines.py
+++ b/software/backend/defines.py
@@ -4,5 +4,7 @@ created by caliskan at 19.04.2023
 contains all constants for the backend architecture of the smart garden project
 """
 
-MQTT_BROKER_LOCAL = ""
+MQTT_BROKER_LOCAL = "lorem ipsum"
 MQTT_BROKER_GLOBAL = "mqtt.eclipseprojects.io"
+RASPI_CLIENT_ID = "lorem ipsum"
+BACKEND_CLIENT_ID = "lorem ipsum"
diff --git a/software/backend/main.py b/software/backend/main.py
index 40a9505..872e863 100644
--- a/software/backend/main.py
+++ b/software/backend/main.py
@@ -11,9 +11,12 @@ Used protocol for interaction: mqtt (paho-mqtt module)
 import paho.mqtt.client as mqtt
 from defines import MQTT_BROKER_LOCAL, MQTT_BROKER_GLOBAL
 from plantdatabase import PlantDataBase
+from data_handling_functions import data_handler
+
 
 def on_message(client, userdata, message):
     print(f'message received! {message.topic}')
+    data_handler(client, message)
 
 
 def on_connect(client, userdata, flags, rc):
@@ -29,11 +32,10 @@ def on_connect(client, userdata, flags, rc):
         client.subscribe("Robot/Data/Picture")
 
         # FrontEnd topics
-        client.subscribe("BackEnd/Data/SensorData")
-        client.subscribe("BackEnd/Data/SensorDataAll")
-        client.subscribe("BackEnd/Data/Position")
-        client.subscribe("BackEnd/Data/Battery")
-        client.subscribe("BackEnd/Data/Picture")
+        client.subscribe("BackEnd/Action/All")
+        client.subscribe("BackEnd/Action/GetPosition")
+        client.subscribe("BackEnd/Action/GetBattery")
+        client.subscribe("BackEnd/Action/GetAllData")
 
         # END TOPIC SUBSCRIPTIONS
     else: