Integrate payment SDKs

We need payments live for the iOS and Android apps next month. Add the payment SDKs used by our engineers into the two codebases, wire the client-side tokenization to our existing checkout flow, and stage the server endpoints so charges can be created. Do the integration in this order: mobile SDKs first, backend webhook handling second, then end-to-end test with a $1 charge on Friday. Confirm the webhook secret and that receipts include the order ID.

Before I hand this to engineering, make the integration reviewer-friendly: surface which SDK versions we will add, where in the codebase the new files go, highlight any breaking changes to our custom card UI, and list the minimum test cases to prove tokenization and 3D Secure flow work. Flag any configuration that will block QA from running end-to-end tests on a staging card.

I pushed the mobile SDK changes and linked the backend webhook handler, then production started failing to ack events. The team lead Mari and DevOps own webhooks; QA is blocked. I’m worried the secret rotation or endpoint URL mismatch caused it but I don’t know which. What’s the likely cause and the safest next step to get events processed without losing customer notifications?

Every payment project costs a week of firefighting: inconsistently deployed SDK versions, undocumented webhook secrets, and no end-to-end test checklist. Where should we standardize to stop repeating this? Recommend concrete habits for versioning SDKs, storing and rotating webhook secrets, and a regression checklist that prevents Friday fire drills.