Your Billing Migration is Really a State Machine

Billing system migration issues often arise due to state synchronization problems between various systems. In a case study, a customer observed duplicate invoices and churn records after migrating a large file-sharing company's quoting and billing system to Salesforce CPQ and Salesforce Billing. The root cause was that each system held a partial copy of the subscription state, and when these copies disagreed, the bugs manifested in customer accounts.

The author, Naresh Goyal, recommends creating an explicit state machine for subscriptions with explicit states and allowed transitions. By clearly defining the transition triggers and owning systems, discrepancies can be minimized. In this case, the false churn problem was resolved by moving failed payments to a Suspended state instead of Cancelled, which improved churn reporting.

The author emphasizes the importance of profiling source data before migration to identify and fix issues early on, rather than discovering them during production. Finally, they suggest cutting over the migration in phases and checking before every switch to ensure a smooth transition.