A billing provider tells your app what happened to a customer, such as a payment that succeeded, a plan that changed, or a subscription that ended. Your app then turns each message into a change in its own database: a plan column, a monthly allowance, or a flag that lets someone in. Those messa...
Source: [Dev.to](https://dev.to/sholajegede/how-to-keep-billing-state-correct-when-webhook-events-repeat-arrive-late-or-fail-2aaj)