How We Run Blue-Green Deployments
The first time I ran a blue-green deployment in anger, it was 6:40 on a Friday evening and the payment authorization service had been down for eleven minutes....
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Tagged #architecture — Page 2
The Case for Boring Technology in Fintech
A few years ago I sat in a postmortem for an outage that cost us most of a business day of failed settlements. The root cause was not a bug in anything we had...
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Building a Rules Engine You Can Actually Maintain
The worst rules engine I ever inherited had 1,847 rules in a single database table, evaluated top to bottom, and the order they ran in was determined by the...
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Observability Beyond Logging
For the first decade of my career, observability meant one thing: logs. When something broke, you SSH'd into a box, tailed a file, and grepped for the word...
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When to Build vs Buy
Every engineering leader I know has a build-versus-buy decision sitting in their backlog right now, and most of them are getting it wrong in one of two...
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Designing a Settlement System
Settlement is the part of a payments business that nobody talks about and everybody fights about in production. It is the machinery that takes the noisy stream...
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Building a Notification Service That Scales
Notifications look like a small feature until you operate one at scale. Then you discover that the humble "we just send the customer an email" requirement is...
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Circuit Breakers and Graceful Degradation
Every distributed system fails. That is not a pessimistic statement; it is an operational one. In the payments platforms I have run, the question was never...
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Designing for Audit Trails from Day One
Every fintech founder I have worked with eventually has the same uncomfortable conversation with an auditor, a regulator, or a partner bank's risk team. The...
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Background Jobs in .NET: A Practical Guide
Every payments platform I have worked on eventually grows a second nervous system. Alongside the request-response code that answers an API call in...
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API Versioning Strategies
Every API I have shipped in a regulated payments environment eventually outlives the assumptions it was born with. A field that was optional becomes mandatory,...
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Building Multi-Currency Support
Every payments platform reaches a moment where a single currency stops being enough. For us it arrived the day a logistics customer in France asked whether...
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