Banks were the first businesses to use computers, but even though I’ve spent the last few years building against bank APIs, I’ve never seen one I particularly liked. A few years ago, I worked at WhatsApp, where we integrated UPI through banks in India to bring the instant payments to a billion WhatsApp users in India. Last year I worked at Modern Treasury, where I built and maintained bank integrations against most of the major banks in the United States. Banks across the world have interfaces that are hard to build against, and I hope I can explain why this is and how we might be able to get out this mess.
Last week, I released iso20022.js, which received over a hundred thousands views, making it to the front page of HackerNews. Clearly programmatically communicating with banks is a huge unsolved problem for developers, and I hope what I’ve learned can be helpful for others that are interested in this space.
A vast majority of the instructions sent to banks do not move through the modern day REST APIs that we are used to, they move through file.