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.
HSM key ceremonies: rehearsed vs. rushed
A key ceremony is a scripted piece of theatre with real cryptographic consequences. The failure modes are entirely operational.
Model budget controls in customer-facing AI
Every LLM feature has an unbounded cost tail. The controls that prevent a support agent from spending your quarter's budget in an afternoon.
The postmortem template that stuck
Most postmortem templates get filled in once and then abandoned. The one that stayed had specific properties worth naming.
USDC on L2s: bridge risk revisited
Layer-2 networks have made stablecoin transfers cheap. The bridge risk that used to concentrate on a few high-profile bridges has changed shape.
Terminal telemetry: what to log, what to drop
The temptation is to log everything. The practical answer is more like ten fields, plus a mechanism for turning on more when you need them.
Idempotency keys: implementation patterns
Every payment API documents idempotency keys. Every payment platform gets some of the details wrong. A pattern guide.
Cross-border retail payments: what still breaks
The last mile of a cross-border transaction still fails in predictable ways. A field taxonomy.
Token vault design: separation of concerns
A token vault is a small service with an outsized responsibility. Common design mistakes and what to do instead.
Hiring for payments engineering: what to test
Generic engineering interviews miss the specific skills payments platforms need. What to add to the loop.
AI-drafted reconciliation reports
LLMs are good at turning structured data into readable prose. Reconciliation summary reporting is a well-shaped use case, with narrow guardrails.