id property
The API message ID, the same value as CreateSingleMessageResponse.id
and the ID messages.get takes.
Since 9 November 2026 this is a hyphenated UUID of 36 characters.
Before, it was the internal AhaSend ID, a different value of 32 hex
characters without hyphens. A message sent before that date can
receive events with either ID for up to 30 days, so group events by
messageIdHeader, not by this ID. messages.get accepts both.
Campaign messages send the same events with an ID of the same format,
which groups their events too. messages.get cannot fetch campaign
messages by it.