talk
· Seoul 2026
Atomic, Reliable, Doomed — A Bitcoin-Fiat QR Payment Post-Mortem
I set out to build a better way to pay QR codes with Bitcoin — no local bank account, no KYC, and unlike existing peer-matched solutions, instant and near-100% reliable on a per-payment basis, by putting one entity on both legs: Lightning in, fiat out, atomically. There was no API for the fiat leg, so I did some magic against the real banking app to make it work. Each payment went through — but the approach itself was fragile, one UI update away from breaking. This talk is a short, honest post-mortem: why the version that actually did the job doesn't survive its own success — one bank account carrying real volume is a regulatory target, and a banking UI automated for payments is a technical one.
15m
agenda
