← The CredPal work03 / CREDPAL · CONTRIBUTION

Payment events become product access.

Keep access aligned with verified payment information.

Where this work fits

Opening checkout does not mean a customer has paid. Confirmation arrives separately, and a subscription can later renew, fail, expire, or be cancelled. Each change needs to leave the account with the right access.

MY CONTRIBUTION

I implemented payment-event verification and handling for subscription changes. Different updates have different consequences, so the work connected trustworthy payment signals with the appropriate account behavior.

THE IDEA, ILLUSTRATED

Verify an event before granting access

PROVIDER → TRUST BOUNDARY → APPLICATION

Payment providerpayment.confirmedSigned event

Signature
check

Awaiting verificationApplication boundary

Provider signatureExpected signature

Test what happens when an event can—or cannot—be trusted.

Receiving a payment event is only the start. Its signature must be verified and its reference matched to a purchase before the customer gets access.

THE ENGINEERING DECISION

Different purchase channels, consistent access.

A card-payment event and an in-app purchase receipt arrive differently and require their own checks. I used signature and receipt verification before updating account access, then handled the subscription states beyond the initial purchase.

The skills behind the work

Webhooks: Receive service updates that happen after the original request has finished.
Signature verification: Check that an incoming event can be trusted before acting on it.
State management: Represent what is happening now and define which changes are valid next.

THE WIDER RESULT

The billing work supported subscription growth and improved transaction success. Customers could move from a verified purchase into the membership features, with access tied to the subscription lifecycle.

Transaction success rate: +40%Improvement following card-payment and transaction-management integrations.

READ THIS IN CONTEXTI connected payment updates to the customer’s subscription. →

Related contributions

A plan becomes a purchaseI integrated payment checkout with account and subscription records. Keeping a purchase attempt connected to its later payment updates helped the product distinguish starting checkout from actually earning access.An iOS receipt joins the same access modelI connected server-side purchase-receipt verification with subscription access. The work helped another purchase channel fit into the account experience without treating an unverified client claim as a completed purchase.Access follows the subscription clockI connected membership state with access to protected product features and worked on lifecycle maintenance. The backend needed to enforce what an account could use as trials and paid periods changed.