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 …
33 pages
Payments
7 min read
ARQC, TC, and AAC: A Field Guide to EMV Application Cryptograms
In EMV chip transactions, the card does not simply return “approved” or “declined” as plain text. It returns an application cryptogram: an 8-byte MAC bound to that transaction’s …
8 min read
The Future of AI in Payments: From Observer to Participant
The next phase of AI in payments is not faster fraud scoring. It is AI moving from an advisory layer that observes the transaction to an actor that initiates payments and operates …
10 min read
Manual Capture: The Two-Step Logic Behind Tap to Pay and Modern Card Payments
Manual capture is not about typing a card number by hand. It is the deliberate split of a card transaction into authorization and capture, managed as a backend state machine. Why …
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 …
5 min read
Where AI Really Fits in POS and E-Commerce Payments
This is part 3 of a series on building grounded AI for payment systems. Part 1 made the case that payments need grounded AI, and part 2 Part 2covered the retrieval pattern that …
5 min read
From Wireless Awareness to Payment Awareness: The RAG Pattern
This is part 2 of a series on building grounded AI for payment systems. Part 1 made the case that payments need grounded AI, not a generic LLM guessing from training data. This …
5 min read
Why Payments Need Grounded AI, Not Just LLMs
This is part 1 of a series on building grounded AI for payment systems. This post sets up the problem. Part 2 covers the retrieval pattern, and part 3 covers the practical use …
13 min read
AI in POS and Payments: From Transaction Processing to Transaction Intelligence
This post looks at where machine learning actually fits in a payment system: not inside the authorization path that EMV, tokenization, and the networks already own, but in the risk …
13 min read
Online vs Offline EMV Transactions: Why Offline Still Matters
Online vs Offline EMV Transactions: Why Offline Still Matters In EMV payments, “online” and “offline” do not mean secure and insecure. They describe where the transaction decision …