Every cross-border payment sets off a quiet chain of checks, banks and security tools. Oluwatimilehin Adesoji builds the systems that keep that chain out of sight.
Adesoji is now Chief Technology Officer (CTO) of HarpFi, a UK-based Electronic Money Institution (EMI) that gives African and international businesses multi-currency accounts and cross-border payouts. He spent seven years at Kora, the pan-African payments company, and is now building a new AI product called Keona. His playbook comes down to a few clear rules: know what must never break, build security on day one, and never make customers feel the pain of moving money.
Adesoji has more than nine years in software, with stops at SB Telecoms, Grocedy, Kora and HarpFi. At Kora he was one of the earliest employees. He started as a backend engineer and rose to engineering lead, helping build the core payment systems while the company was still small. He says that gave him hands-on lessons in licensing, compliance and getting things right. Working close to the details, he learned what regulators accept and what they do not, and what customers expect on flexibility and security. Because financial systems attract attacks, he says, security has to be watched from the first day.
That experience shapes how he leads at HarpFi. His first rule is to sort a system into what is critical and what is not. A fintech product is sensitive, he says, but not every part is equally so. Startups need to move fast, so the team must know which parts can change quickly. For the critical parts, there is no shortcut. Clear guidelines come first, and teams must take the time the change needs.
His second rule is to keep learning. AI is making cyber threats more advanced, and bad actors are adapting fast. Adesoji says teams must keep upskilling, learn from other firms’ experience and stay on top of new risks.
His third rule is about the customer. Money should move without the user seeing the mess behind it. A business in Africa that needs funds abroad should not have to chase someone for a conversion, or wonder if the money will arrive. Hiding that complexity is hard, he says, and it works only with the right partners.
| Adesoji’s rule | What it means in practice |
|---|---|
| Know what is critical. | No shortcuts on core payment systems. |
| Security from day one. | Attacks start as soon as money moves. |
| Hide the complexity. | Customers should not feel cross-border friction. |
| Clear expectations. | Everyone knows the goal and the guardrails. |
| Basics before AI. | AI is a booster, not a replacement for skill. |
Adesoji also builds outside banking. He co-founded Inga, a bookmarking app, and Rivva, an AI productivity app that plans tasks around a user’s energy levels. Both have ended active development. He is now working on Keona, an AI customer assistant for websites. He says he tries not to carry the full rigidity of fintech security into non-financial products. But AI tools still handle customer data, so he borrows pieces of the security mindset and adapts them, while still moving fast.
As a leader, he says his biggest lesson is to set clear expectations and make sure everyone shares them. Teams also need the right tools and guardrails. AI helps people move faster, he says, but everyone must still be responsible for building things right.
He mentors through The Curve, Code Your Future and ADPList. His own start came through an IBM community programme at university, and he says he might never have entered tech without it. He sees many new developers lean too hard on generative AI. His advice is to learn the basics first. In his words, grounding in the fundamentals, together with AI, is what gives “superpowers.”
Looking ahead, he is most excited by stablecoins. He points to firms like Stripe entering the space, and expects blockchain rails to ease the movement of money across borders.
Why it matters: Africa’s payments boom depends on trust. Founders who build safe systems early, and hide the pain of cross-border money, win customers who may never think about the tech. Adesoji’s path from a small startup to a CTO seat shows what deep, hands-on experience in a young fintech can build. His warning to early-career engineers is just as useful: AI speeds up good engineers, but it does not replace the basics.
What to watch next: how HarpFi grows its African and international customer base, and whether stablecoin rails become part of its offer. Also watch whether Keona launches and finds users, and how more African fintech talent moves from startups into leadership roles abroad.
Sources: Profile of HarpFi CTO Oluwatimilehin Adesoji by Blessed Frank.
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