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:

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, pricing page handoff, and smoke test

I am not dropping a checkout link into a blog post. If you have a live Stripe/Supabase/Cloudflare/Vercel billing path and want me to take the first sprint, reply with:

1. repo or relevant code paths
2. what payment state should unlock
3. current deploy target
4. whether test-mode Stripe keys/webhook secret are ready

I will send a fixed scope and payment link only if it is a fit.

GitHub: https://github.com/sravan27