To actually do a distributed transaction, I would look into algorithms such as 2PC or 3PC. Although before going there, I would seriously consider consolidating

To actually do a distributed transaction, I would look into algorithms such as 2PC or 3PC. Although before going there, I would seriously consider consolidating different backends into one scalable option (banking transaction example is a bit contrived, although I gather the author is just trying to make a point). At the service level integration, we can leverage a reliable message queue middleware to make sure a task is eventually delivered and handled (or be put in a dead letter queue so we can do a batch clean up) Also as a general principle, I would make each of those sub-transactions to be idempotent, so that retrying multiple times won't hurt, and there would be a natural way of picking the winner if there are conflicting ongoing commit / retry attempts.