11 min read
Every Payment Has a Liability Owner
EMV authorization is the easy part. The hard problems are timeouts, retries, SoftPOS lifecycle gaps, store-and-forward declines, and the financial question that remains when two …
4 pages
Reversal
8 min read
Double Charges: The Hardest Problem in Payments Is Remembering You Already Did
A duplicate charge is rarely a coding bug. It is a distributed system losing certainty about whether an authorization already happened — and then guessing wrong. Why blind retries …
8 min read
Partial approvals: what terminals and hosts must do when the card pays only part
A partial approval is not a decline and not a completed sale. ISO 8583 response codes and amount fields must be read together — and the terminal must not show a green APPROVED …
10 min read
Reversals, Refunds, and Chargebacks: Decoding the Payment Lifecycle
Three words every payment professional uses — and confuses. Each lives at a different point in the settlement lifecycle, under a different protocol, with radically different …