Context
A financial calculation must stay consistent as it becomes a proposal and then a payment. PixPan combines direct and reverse calculations, rate tables, physical and digital operations, and team oversight. The challenge was connecting these stages while retaining the terms originally shown to the customer and operator.
My contribution
At PuggyWare, I worked across the product, connecting the web experience, calculation rules, persistence, payment integration, and operational tracking. I also contributed to decisions around permissions, reporting, and recovery when events arrive outside the expected flow.
How it works
- The calculation starts from the desired net amount or the amount to charge, applying the authorized rate table and installments.
- The proposal stores the calculated terms. Creating or reusing a payment link respects that proposal's version.
- The webhook is validated and persisted in an inbox before processing, with duplicate handling and retries.
- The processor checks amount, currency, and recipient; reconciliation recovers pending work and reports respect the user's scope.
Technical decisions
Preserve commercial terms
Decimal calculations and proposal snapshots keep amounts tied to the rates authorized for that operation. Changing a rate table should not silently rewrite terms already presented.
Make confirmation durable
A persisted inbox, leased processing, and reconciliation separate receiving an event from applying it. This supports recovery and repeated notifications without depending on one successful request.
What I learned
I learned to treat financial state as a sequence of evidence: a calculation, a proposal, and a confirmation carry different responsibilities. Making these transitions explicit supports both the operator experience and investigation of inconsistencies.
Limits and next steps
- Confirming a gateway payment does not establish an automatic Pix disbursement to the recipient.
- The image shows the public website; customer data, proposals, and operational results are not displayed.
Credits
Developed at PuggyWare in collaboration with the team.