The first time you take a cut of someone else's money, you make a decision about custody. Most people make it without knowing they made it. You do the obvious thing — the whole payment lands in your account, it settles, you take your piece, and you s...

A reservation cancellation is usually implemented as one action. A replacement booking is implemented as another. That separation creates the most dangerous moment in the workflow: the original reservation can be released before the replacement is ...

Most software systems are comfortable returning incomplete answers. An API returns null. A model returns a low-confidence score. A workflow enters an undefined status. A human operator is left to infer what the system failed to decide. That may be ...

Most systems optimize for getting an answer. Some have to optimize for never getting the wrong one. Here's how building for asymmetric error costs changes everything about your architecture. Two kinds of "wrong" Most of the systems we build are qui...