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.
Handling partial reversals
Full reversals are well-covered in most integrations. Partial reversals are where the design assumptions leak.
TLS 1.3 in device fleets
TLS 1.3 became mandatory in most compliance frameworks by 2025. Deploying it across a device fleet has some rougher edges than the browser story suggested.
Documentation as an engineering deliverable
Documentation gets treated as an aftermath. Treating it as a deliverable — with the same discipline as code — changes what the team ships.
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.
RAG over compliance documents
Compliance documents change slowly, are consulted often, and require precise citation. A well-shaped RAG use case with specific engineering demands.
The custody question for merchant payouts
Merchant payouts in stablecoins raise a custody question that fiat payouts don't. What operational patterns look like.
Certificate pinning on Android POS
Pinning is a defense against a specific attack. On an Android POS fleet, the wrong pinning strategy is the operational problem that never leaves.
The reporting store vs. the transaction store
One database can serve both operational and reporting queries — until it can't. Where the split should go and how to build it.
The disappearing signature: chip-and-PIN in North America
Signature-based card verification in the US is quietly winding down. The remaining edge cases are worth planning around.
The one-on-one that actually helps
Most one-on-ones are status updates. The ones that build the relationship and surface problems have a different shape.