diff --git a/swh/scheduler/celery_backend/config.py b/swh/scheduler/celery_backend/config.py
--- a/swh/scheduler/celery_backend/config.py
+++ b/swh/scheduler/celery_backend/config.py
@@ -19,6 +19,9 @@
 
 from swh.core.config import load_named_config
 from swh.core.logger import JournalHandler
+from kombu.serialization import register
+from swh.core.serializers import swh_json_dumps, swh_json_loads
+
 
 DEFAULT_CONFIG_NAME = 'worker'
 CONFIG_NAME_ENVVAR = 'SWH_WORKER_INSTANCE'
@@ -143,6 +146,12 @@
 for queue in CONFIG['task_queues']:
     CELERY_QUEUES.append(Queue(queue, Exchange(queue), routing_key=queue))
 
+
+register('swhjson', swh_json_dumps, swh_json_loads,
+         content_type='application/json',
+         content_encoding='utf-8')
+
+
 # Instantiate the Celery app
 app = CustomCelery()
 app.conf.update(
@@ -156,13 +165,15 @@
     # Time (in seconds, or a timedelta object) for when after stored task
     # tombstones will be deleted. None means to never expire results.
     CELERY_TASK_RESULT_EXPIRES=None,
+    CELERY_TASK_SERIALIZER='swhjson',
+    # CELERY_RESULT_SERIALIZER='swhjson',
     # Late ack means the task messages will be acknowledged after the task has
     # been executed, not just before, which is the default behavior.
     CELERY_ACKS_LATE=True,
     # A string identifying the default serialization method to use.
     # Can be pickle (default), json, yaml, msgpack or any custom serialization
     # methods that have been registered with kombu.serialization.registry
-    CELERY_ACCEPT_CONTENT=['msgpack', 'json', 'pickle'],
+    CELERY_ACCEPT_CONTENT=['msgpack', 'swhjson', 'pickle'],
     # If True the task will report its status as “started”
     # when the task is executed by a worker.
     CELERY_TRACK_STARTED=True,