Presentation: Architecting a Modern Financial Institution

I am the co-founder and CTO of Nubank which is a tech company competing with traditional banks. We're based in São Paulo, Brazil and have over 2.5 million customers using our credit card product. We’ve also recently launched a checking/savings/digital payments account to address a much larger market.

Nubank has focused on functional programming from the very beginning of the company, and we’ve emphasized immutability and simplicity (all the way to the database). Our stack includes Clojure, Datomic, and Kafka (fairly bleeding edge stuff in 2013), and at over 100 engineers and millions of customers, we’ve enjoyed seeing this architecture scale nicely in a complex domain. I think there are some interesting learnings in terms of how the architecture has emerged under these circumstances.

I also think it is interesting that we are building a bank versus any other sort of technology company. While many aspects of building technology remain the same, there are interesting architecture and cultural implications driven by being responsible for money, being regulated, and being required to interoperate with predominantly legacy companies and technologies at the borders. I think there are some some hard-won insights to share, and hope this will be an interesting talk for the audience.

This talk is primarily targeted at working engineers who are designing, building, and scaling services in production. For those thinking about scalability, architecture tradeoffs, and service boundaries.

I think the talk will also be interesting for those who are curious about the inner workings of core banking and credit card systems (as opposed to e-commerce or something like that), including relevant differences driven by working in a highly regulated industry.

A lot of people dabble in functional programming (and languages like Clojure) in an academic setting and for side projects, but it’s a bit less common to see these patterns in production at scale. I think that's pretty interesting. I hope people take away from it that these design principles aren’t just for academics and weird guys. I also hope that some of the decisions we’ve made and our resulting experience will provide some interesting points of reference for audience members to take back to their day jobs.

My largest concern at the moment is as much social as it is technical: the scalability of our interface with our customers (or “operations” in the financial services industry). Unlike Google (who can make it difficult for their customers to reach them), we have a regulatory and fiduciary responsibility to answer the questions we receive. From a customer perspective, it's your money, and it’s important. So I think a lot about how we can maintain a phenomenal customer experience while leveraging technology in the right way so that we scale efficiently (especially from a cultural perspective).