> Anything that guarantees exactly once is selling snake oil.

That's a pretty spicy take. I'll agree that exactly-once is hard, but it's not impossible. Obviously there are caveats, but the beauty of DBOS using Postgres as the method of coordination instead of the an external server (like Temporal or Inngest) is that the exactly-once guarantees of Postgres can carry over to the application. Especially so if you're using that same Postgres to store your application data.