Most of us expect money to go where we tell it to. The common mental model of monetary transactions is that money moves at the speed of light. But everything in the world is some kind of engineering, and we rarely think about the systems working behind the scenes.

Yet, having spent much of my career in financial infrastructure, I know that what appears to be a simple transaction can involve a surprisingly complicated network of applications, payment infrastructure, and legacy technology. A 2025 U.S. government report found that 8 out of 11 critical legacy IT systems examined still used outdated programming languages.

One of the biggest mistakes I see organizations make is looking at modernization as a piecemeal affair. Companies replace one application or install new software and assume they are done for the next decade.

Installing a modern system does not necessarily make the whole infrastructure modern. I have seen how ancient technology like file-based integrations and CSV files is used to connect systems, and, in my experience, these dependencies can and often do produce legacy issues while modernization takes place.

In core banking, these issues come to the fore immediately. I have seen the scale of these undertakings, including the work I did back........

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