diff --git a/definitions/3.0.0/messageExampleObject.json b/definitions/3.0.0/messageExampleObject.json
index 3a59ffcf..316e0759 100644
--- a/definitions/3.0.0/messageExampleObject.json
+++ b/definitions/3.0.0/messageExampleObject.json
@@ -24,9 +24,10 @@
     },
     "headers": {
       "type": "object",
-      "description": "Example of the application headers. It can be of any type."
+      "description": "Example of the application headers. It MUST be a map of key-value pairs."
     },
     "payload": {
+      "type": ["number", "string", "boolean", "object", "array", "null"],
       "description": "Example of the message payload. It can be of any type."
     }
   },