“Stripe just wants a number. It doesn’t care how we get there.”
Billing logic spreads because people call the payment API wherever the event happens, and then it lives in fifty places. Mikaelian’s fix is to emit billable facts and reconcile them separately, keeping the provider at the edge instead of threaded through the product. The payoff he names is onboarding, since a new engineer can change product code without first learning how the company charges anyone. Anyone who has grepped a codebase for charge calls knows the failure this avoids.