Blog & insights.
Writing from our founder, Anselm Fowel — on fintech, engineering leadership, product craft, and building at scale. Articles live on anselmfowel.com and stream in here as they are published.
Handling Money Rounding Across Currencies
A support ticket landed on my desk a few years ago with the subject line "invoice off by one cent." A merchant in the Netherlands had split a €100.00 order...
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The First Rule of Incident Communication
At 2:14 on a Tuesday afternoon, our payment authorization service started rejecting one in every three card transactions. I know the exact time because the...
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The Hidden Cost of an ORM
A few years ago I spent the better part of a Friday night staring at a payment reconciliation job that had gone from taking ninety seconds to taking forty...
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How to Rebuild Trust After You Have Lost It
Four years ago I shipped a change to our settlement engine on a Thursday afternoon, right before a long weekend, because I was convinced it was low risk. It...
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Building a Health Check That Means Something
The worst outage I ever sat through lasted four hours, and for the first two of them every dashboard we owned was green. The load balancer was happily routing...
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Leading Hybrid Teams Without a Two-Tier Culture
The clearest sign that a hybrid team has split into two tiers is a decision that gets made twice. Once in the room, over lunch or at someone's desk, and again...
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Why We Log in JSON
Three years ago I spent a Saturday night grepping through 40 gigabytes of plaintext logs trying to work out why a batch of settlement files had gone missing....
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The Underrated Power of a Team Wiki
We lost a payments engineer named Priya to a competitor in the middle of a PSD2 migration. She gave three weeks' notice, which is generous, and I still...
Read articleDesigning an Audit Log That Scales
The first time an auditor asked me to prove who changed a customer's credit limit on a specific Tuesday eight months earlier, I learned exactly how good our...
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