Author here. I’ve spent quite some time building the payout side of a cross-border payments platform, mostly the routing engine.

The thing that surprised me most was that what looks like one international transfer is really a series of local payments, and the money usually doesn’t cross the border when you hit send.

The hardest bug class was timeouts. When a partner doesn’t answer, you don’t know if the money went through, and retrying can pay someone twice. We handle that with status checks using the same reference.

We learned it the hard way when we relied on one partner for one of our major routes, and when it went down, most of our payouts failed with it.

Curious how others handle the “unknown” state. Happy to answer questions