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.
CBDC pilots: a comparative note
Central bank digital currency pilots continued in 2025 across multiple jurisdictions. What the different designs reveal about the choices ahead.
Wallet interoperability across South-East Asia
Regional QR interoperability is real, but the fine print keeps the promise from arriving evenly across markets.
SoftPOS: reading card data without a magstripe
SoftPOS acceptance has passed the novelty stage. What the integration realities look like now that the certifications are stable.
Event sourcing for transaction platforms
Event sourcing is often oversold. For a payment transaction platform, though, its properties align well — with some carve-outs.
3DS 2.3: challenge flow decisions
EMV 3DS 2.3 moves several decisions from the issuer to the ACS, and from the ACS to real-time context. What that means for merchants.
Splitting a monolith without a rewrite
"Break up the monolith" is often shorthand for "rewrite the system". A more disciplined approach that ships.
Explaining a declined transaction with an LLM
A merchant asking "why was this declined?" is a common support ticket. What a well-designed LLM assist looks like — and where it must refuse.
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.
Smart contract wallets for payment agents
Smart contract wallets and account abstraction give agent-initiated payments a technical foundation that programmatic keys don't have.
EMV kernel updates: navigating certification
Kernel updates arrive with regularity, and each one triggers a certification cycle. What actually goes wrong.