At CredPal, I built subscription billing with trials and automated payment updates, integrated payment services, and worked on email and push notifications. I also built the account and planning features behind a membership product, connecting a purchase to something a customer could use.
My CredPal work covered payments and customer communication, including a subscription product with meal planning. Product, finance, and support needed billing behavior that matched what customers were told.
01 / Payments & subscriptions
I connected payment updates to the customer’s subscription.
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 built subscription billing with free trials and automated payment updates, integrated payment services, and connected purchase verification to membership. I worked with product, finance, and support on the billing flows and their customer-facing consequences.
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 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.
WHAT CHANGED
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.
Subscriptions in 3 months
+50%Growth after launching billing with free trials and webhook automation.
Tools & engineeringPayment APIs & webhooks · Signature and receipt verification · Relational data & access guards
The skills behind the work
Payment APIs & webhooks
Receive and reconcile purchase updates from payment services.
Signature and receipt verification
Check a payment signal before allowing it to change access.
Relational data & access guards
Connect subscription state with the account and features it belongs to.
I sent each customer the right message at the right time.
Messages only help when they reach the right person at a useful time. A push can be missed, so customers also needed relevant email and a place to return to notifications.
MY CONTRIBUTION
I integrated email and push notifications, tailored messages to customer activity, and scheduled delivery for relevant moments. A saved inbox kept notifications available after the initial push.
THE IDEA, ILLUSTRATED
Schedule a tailored message across channels
TAILORED. SCHEDULED. DELIVERED.
9:41•••
YOUR INBOX
CUSTOMER UPDATE
Your notifications, in one place.
Delivered messages stay available to revisit.
Unread · saved in your inbox
Customer activity shapes the message and timing. Email and push deliver it, while the inbox keeps it available to revisit.
Customer activity shapes the message and timing. Email or push delivers it, while the inbox keeps it available to revisit.
THE DECISION
Match the message and timing to the customer.
Timing and audience mattered as much as the channel. I aligned sends with customer activity, filtered invalid device recipients, and kept a saved inbox so a missed push did not lose the message.
WHAT CHANGED
Tailored, scheduled email and push notifications helped increase customer engagement by 30%.
Customer engagement
+30%Increase associated with tailored, scheduled email and push notifications.
I turned reusable meal plans into personal schedules.
A meal-plan template still needs dates, recipes, and progress before a customer can follow it. People also need to find suitable content, save choices, and turn ingredients into a shopping list.
MY CONTRIBUTION
I built backend features for expert-created and personal plans, recipe discovery, shopping lists, and sharing. Activating a plan connected its reusable content to a customer’s own schedule and membership.
A plan is more than access: it gives the customer something practical to follow.
A reusable plan becomes a personal calendar. Each customer gets their own dates and progress, without changing the original plan.
THE DECISION
Share the content, keep progress personal.
The original plan and a customer’s copy had different jobs. I modeled personal dates and completion separately, checked membership for premium activation, and handled conflicts such as placing two meals in the same slot. Catalogue filters helped narrow the recipes people could choose from.
WHAT CHANGED
Membership gave customers a plan they could start and follow, with saved choices and progress. Recipe ingredients could become a reusable shopping checklist.
This work involved product, finance, and support as well as engineering. Billing rules had to become consistent account behavior, and customers needed to understand what had happened to their payment or subscription.
“He consistently demonstrated strong technical ability, reliability, and a willingness to take ownership of his work.”