System Design
A payment system that refuses to guess
The second in the series: a system where the dangerous failure is not downtime but doubt, and where the guardrails exist to stop the machine resolving that doubt with optimism.
Payments
Payments
Moving money is hard
Most software engineers think a payment is a database transaction. The payments industry has spent decades proving otherwise.
Computer Science
Building a double-entry ledger in 200 lines
Every system that tracks value eventually needs a ledger, and most start with a balance column and a sense of optimism. The fix is double-entry bookkeeping: five hundred years old, and small enough to build in an afternoon.