I keep finding the same Stripe webhook bugs in SaaS launches

I keep finding the same Stripe webhook bugs in SaaS launches Most early SaaS billing bugs are not in Stripe Checkout itself. They are in the glue around it: trusting the success redirect instead of the signed webhook parsing JSON before signature verification missing idempotency for retry events reflecting verifier errors from unauthenticated webhook routes updating subscription state without a replay/audit trail letting "Pro" access drift from the payment source of truth Over the last few days I have been shipping small public fixes around exactly this class of problem. Recent examples: Morphix: Cloudflare Worker Stripe webhook with signature verification, Supabase subscription sync, and event idempotency ledger https://github.com/yiyuanlee/morphix/pull/25 Open Mercato: hardened unauthenticated payment/shipping provider webhooks against raw verifier error reflection and missing rate limiting https://github.com/open-mercato/open-mercato/pull/2680 Covenant: webhook signatures hardened against replay and secret rotation gaps https://github.com/wienerlabs/covenant/pull/229 Volunteerflow: made a Stripe invoice.paid Founders Circle counter update transactional instead of partially committing user/counter state https://github.com/ppppowers/volunteerflow-project/pull/49 The pattern is boring in the best possible way: payment systems should be boring. The 48-hour version For a small SaaS that is about to turn on paid plans, I can take a bounded payment assurance sprint: inspect Checkout / webhook / subscription state flow verify signed webhook handling and raw-body behavior add idempotency around Stripe retry events ensure subscription status and entitlement state have one source of truth add a small regression test or smoke script leave a deploy/runbook note so the next failure is diagnosable Fixed scopes I am taking: $2,000 / 48 hours: one payment path hardened and documented $5,000 / 5 days: full launch pass across Checkout, webhook, subscription mirror, Pro gate, pricin