Checkout Test Matrix and Realistic User Journeys
Test guest and authenticated flows, single‑item and multi‑item carts, renewals, upgrades, and prorations. Validate taxes, discounts, and currency conversions. Use accessibility checks and low‑bandwidth simulations. Confirm error messages teach, not scold. Test receipts, invoices, and dunning emails. Prove that failing gracefully preserves intent to buy. A humble spreadsheet listing scenarios, expected outcomes, and evidence screenshots beats forgotten edge cases that only surface when your first campaign finally lands.
Webhook Reliability, Retries, and Idempotency Keys
Assume webhooks arrive late, twice, or never. Store idempotency keys, log signatures, and verify payload authenticity. Queue processing with exponential backoff and dead‑letter capture. Surface operational dashboards that turn mysteries into obvious fixes. When events misfire, avoid side effects by re‑querying processor state. A crisp runbook saves your Sunday and lets junior teammates recover calmly. Stability here is invisible to customers—but processors and accountants notice when everything simply reconciles.