diff --git a/platypush/__init__.py b/platypush/__init__.py
index e9fa0b12..e2eb2dbc 100644
--- a/platypush/__init__.py
+++ b/platypush/__init__.py
@@ -163,7 +163,7 @@ def get_default_pusher_backend(config):
 
 def get_device_id():
     global config
-    return config['device_id']
+    return config['device_id'] if 'device_id' in config else None
 
 
 def main():
diff --git a/platypush/backend/__init__.py b/platypush/backend/__init__.py
index 47f34b6d..bdf564e7 100644
--- a/platypush/backend/__init__.py
+++ b/platypush/backend/__init__.py
@@ -1,4 +1,5 @@
 import logging
+import socket
 import platypush
 
 from threading import Thread
@@ -29,6 +30,7 @@ class Backend(Thread):
         self.on_init = on_init
         self.on_close = on_close
         self.on_error = on_error
+        self.device_id = platypush.get_device_id() or socket.gethostname()
 
         Thread.__init__(self)
         logging.basicConfig(level=logging.INFO
@@ -48,7 +50,7 @@ class Backend(Thread):
             return  # No target
 
         target = msg.pop('target')
-        if target != platypush.get_device_id() and not self.is_local():
+        if target != self.device_id and not self.is_local():
             return  # Not for me
 
         if 'action' not in msg:
diff --git a/platypush/backend/kafka/__init__.py b/platypush/backend/kafka/__init__.py
index 9ce04be0..c494351e 100644
--- a/platypush/backend/kafka/__init__.py
+++ b/platypush/backend/kafka/__init__.py
@@ -8,7 +8,8 @@ from .. import Backend
 class KafkaBackend(Backend):
     def _init(self, server, topic):
         self.server = server
-        self.topic = topic
+        self.topic_prefix = topic
+        self.topic = topic + '.' + self.device_id
         self.producer = None
 
     def _on_record(self, record):
@@ -27,16 +28,17 @@ class KafkaBackend(Backend):
             self.producer = KafkaProducer(bootstrap_servers=self.server)
 
     def send_msg(self, msg):
-        if isinstance(msg, dict):
-            msg = json.dumps(msg)
         if isinstance(msg, str):
-            msg = msg.encode('utf-8')
+            msg = json.loads(msg)
+        if isinstance(msg, dict):
+            target = msg['target']
+            msg = json.dumps(msg).encode('utf-8')
         if not isinstance(msg, bytes):
             msg = json.dumps(msg)
             raise RuntimeError('Invalid non-JSON message')
 
         self._init_producer()
-        self.producer.send(self.topic, msg)
+        self.producer.send(self.topic_prefix + '.' + target, msg)
         self.producer.flush()
 
     def run(self):