diff --git a/src/aleph/web/controllers/messages.py b/src/aleph/web/controllers/messages.py
index 723d3e9ac..fa7a60cc4 100644
--- a/src/aleph/web/controllers/messages.py
+++ b/src/aleph/web/controllers/messages.py
@@ -264,7 +264,7 @@ def validate_field_dependencies(self):
 
 
 def message_to_dict(message: MessageDb) -> Dict[str, Any]:
-    message_dict = message.to_dict()
+    message_dict = message.to_dict(exclude={"content_type"})
     message_dict["time"] = message.time.timestamp()
     confirmations = [
         {"chain": c.chain, "hash": c.hash, "height": c.height}