Writing
Notes from systems meeting real devices.
Notes on payment systems, device software, transaction uncertainty, platform design, and the emerging role of AI in commerce. I write from the questions that appear in real operating conditions.
PSD3 and the merchant integration checklist
Payment Services Directive 3 and the Payment Services Regulation land in staggered dates through 2027. Here's what merchant integrators need to prepare for now.
SEPA Instant: verification of payee in practice
Verification of payee became mandatory across SEPA in October 2025. The first months in the field show a predictable pattern of edge cases.
FedNow at scale: three years in
The Federal Reserve's instant payment service crossed its third live year in July 2026. Adoption looks different from what the launch materials promised.
Cross-border retail payments: what still breaks
The last mile of a cross-border transaction still fails in predictable ways. A field taxonomy.
Wallet interoperability across South-East Asia
Regional QR interoperability is real, but the fine print keeps the promise from arriving evenly across markets.
Chargeback economics for small merchants
Below a certain volume, the chargeback loss isn't the problem — the response cost is. What a defensible response process looks like.
Real-time payments in India: UPI Global rollout
NPCI's cross-border UPI push is on. What the receiving markets are learning about live-integrated retail payments from India.
Authorization economics: scheme fees decoded
The interchange bill is the visible part. What actually shows up on the underlying scheme fee statement is where the interesting rebalancing is happening.
Why cash-out still matters in emerging markets
The digital payments story misses the operator on the corner. Some design considerations for cash-out that don't come up in western integrations.
Card-not-present fraud patterns, 2024
What the year's CNP fraud looked like — signal patterns, response effectiveness, and where the loss actually landed.