diff --git a/platypush/backend/http/__init__.py b/platypush/backend/http/__init__.py
index cb825f65..185a51d7 100644
--- a/platypush/backend/http/__init__.py
+++ b/platypush/backend/http/__init__.py
@@ -149,7 +149,7 @@ class HttpBackend(Backend):
 
             redis = self._get_redis()
             if redis:
-                redis.rpush(self.redis_queue, stop_evt)
+                redis.rpush(self.redis_queue, str(stop_evt))
 
         if self.server_proc:
             self.server_proc.terminate()
@@ -284,7 +284,7 @@ class HttpBackend(Backend):
 
             redis = self._get_redis()
             if redis:
-                redis.rpush(self.redis_queue, event)
+                redis.rpush(self.redis_queue, str(event))
             return jsonify({ 'status': 'ok' })
 
         @app.route('/static/<path>', methods=['GET'])
diff --git a/platypush/backend/redis.py b/platypush/backend/redis.py
index 352f9215..3d4dd0e0 100644
--- a/platypush/backend/redis.py
+++ b/platypush/backend/redis.py
@@ -35,6 +35,7 @@ class RedisBackend(Backend):
 
 
     def send_message(self, msg, queue_name=None):
+        msg = str(msg)
         if queue_name:
             self.redis.rpush(queue_name, msg)
         else:
diff --git a/platypush/plugins/adafruit/io.py b/platypush/plugins/adafruit/io.py
index 0a5b8d1a..0ce56dc3 100644
--- a/platypush/plugins/adafruit/io.py
+++ b/platypush/plugins/adafruit/io.py
@@ -1,5 +1,6 @@
 import ast
 import statistics
+import json
 import time
 
 from threading import Thread, Lock
@@ -141,7 +142,7 @@ class AdafruitIoPlugin(Plugin):
         else:
             # Otherwise send it to the Redis queue to be picked up by the throttler thread
             redis = self._get_redis()
-            redis.rpush(self._DATA_THROTTLER_QUEUE, {feed:value})
+            redis.rpush(self._DATA_THROTTLER_QUEUE, json.dumps({feed:value}))
 
 
     @action