Fintech

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Fintech· Feb 14, 2026

The Engineering Lessons From $50M in Processed Transactions

Processing large volumes of money teaches you things about distributed systems that no textbook covers.

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Fintech· Jul 25, 2023

My Approach to Code That Touches Money

Financial code deserves a higher standard of rigour than general application code. Here is what that higher standard looks like in practice.

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Fintech· May 01, 2023

Webhook Security: What Most Developers Skip

Webhooks are a common attack vector that most developers implement insecurely.

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Fintech· Apr 11, 2022

PCI-DSS Is Not a Checkbox. It Is a Discipline.

Passing a PCI-DSS audit does not mean your system is secure. It means it was secure when audited.

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Fintech· Jan 17, 2022

Building Multi-Currency Systems That Do Not Lie

Currency arithmetic in floating point is broken. Here is how to build currency systems that are always correct.

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Fintech· Nov 29, 2021

Idempotency Is Not Optional in Payment Systems

Your payment API will receive duplicate requests. Idempotency is what makes the second request harmless.

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Fintech· Mar 12, 2017

Fraud Smells Like a Pattern

Most fraud is not clever. It is repetitive. On building fraud detection — and why fraud is detectable before it is paid.

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Fintech· Aug 30, 2016

Payments Are Not a Feature. They Are an Infrastructure.

I have processed $8M+ across international gateways. Payment integration is one of the hardest engineering problems you will face.

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Fintech· Sep 20, 2010

The Double-Entry Principle: Why Financial Systems Cannot Afford Bugs

In accounting, every debit must have a credit. In financial software, every decision must have a consequence.