Mule Message Structure
The Mule message is the data that passes through flows inside your Mule application.
It consists of two main parts:
The message attributes, which contains metadata from and attributes of the Mule message.
The message payload, which contains the core information of the Mule message.
The metadata contained in the message header consists of attributes which provide process related information about the message.
Each individual attribute has a name and a value. The name is how you refer to the attribute, and the value is the information stored within it.
The message payload is the most important part of the Mule message because it contains the data your Mule application processes. You may apply metadata in the message header to communicate information about your message or secure it from being tampered with, but the core of the message – the data you are transporting – is the reason the message exists in the first place.
Each Event Processor that receives a Mule Event, returns a new Mule Message. Meaning that each Event Processor returns a new payload.