How one company silently migrated 20,000+ customers across Stripe accounts

A software company successfully migrated over 20,000 US customers from its Australian Stripe account to a new US-based one last month, with no service disruptions or customer-facing changes. The migration covered payment methods, subscriptions, credits, coupons, and promotional codes across both a tutoring product and a schools product. Engineers built custom Go scripts with dry-run modes to safely transfer data, carefully reconciling coupon and promo code usage limits that had been stored inconsistently. One of the trickier challenges involved in-flight invoices, which were left on the old account for a 48-hour window to allow natural retries and customer payments to settle before being voided and recreated on the new account. No customers were double-charged, lost access, or received any notification, as the transition was entirely invisible from their end.