Buttondown Documentation
As a helpful primer for the diagram below, here's a quick run-through.
(Transactional emails are intentionally omitted from the diagram above, as they don't enter the workflow at all.)
That is, obviously, a lot to take in. If you're just trying to understand for the first time how emails move through the workflow, here's a simplified diagram with some edge cases removed:
Represents the state of an email.
No action is required to move from one state or another; Buttondown internally handles the transitions, and exposing the status is for observability purposes only.