In the classic paper Data on the Outside versus Data on the Inside Pat Helland argued that data within a service boundary should be treated differently than data residing outside of it.
Here, I shall argue that the same applies to messages. Inside a boundary messages are tightly coupled to the corresponding data manipulations. It may be even possible to enforce total order of messages.
When the message crosses the boundary, it enters the no man's land where bad things happen. Messages get reordered, duplicated or even lost.
Join me to see how to get your messages safely to the other side