Some of the most consequential infrastructure in global financial technology is the kind users never see. Behind every enterprise cross-border payout or liquidity conversion across jurisdictions sits a dense web of regulatory checks, banking rails, and security protocols firing in the background. For Oluwatimilehin Adesoji, Chief Technology Officer at UK-based Electronic Money Institution (EMI) HarpFi, making that labyrinth invisible to businesses has become the defining mission of his career.

Adesoji brings more than nine years of software engineering experience to the role, built across stints at technology companies including SB Telecoms, Grocedy, pan-African payments company Kora, and now HarpFi. Over that span he has grown from a hands-on backend builder into a technical executive, a trajectory that mirrors the maturation of the African and global fintech ecosystems.

Seven Years Building Kora's Payment Core

Before stepping into the C-suite at HarpFi, Adesoji spent seven formative years at Kora as one of the company's earliest employees, serving as a backend engineer and later an engineering lead. Joining while the company was still in its infancy allowed him to help architect and manage its core payment infrastructure from the ground up.

"Spending seven years at Kora when it was still very much a startup, and having to navigate all of the challenges that come with startup licensing, compliance, and getting things right, gave me hands-on experience," Adesoji recalls. "The team was still quite small before it grew large, and I was able to be in the details of several things."

Operating at the heart of a rapidly scaling payment processor exposed him early to the non-negotiable realities of financial systems, forcing a balance between customer demands for flexibility, strict regulatory oversight, and relentless cyber threats.

"It exposed me to what is acceptable and what is not acceptable from a regulatory and compliance standpoint when building a sensitive financial system, as well as customer expectations around flexibility and security," he explains. "Because of the business sensitivity of a financial system, you definitely get threats and attacks, so security is something you have to pay attention to right from day one. All of those experiences gained at Kora shaped my knowledge going into HarpFi and building a banking solution for businesses."

Engineering Resilience and Abstracting Complexity at HarpFi

Today, as CTO of HarpFi, Adesoji leads the technical strategy for a UK-based EMI — a category of firm authorized under UK regulation to issue electronic money and provide payment services — that provides reliable global banking solutions to both African and international enterprises, including multi-currency accounts and seamless cross-border payouts. Regulated non-bank institutions of this kind now sit at the center of a growing share of global payment activity, which is why the reliability of the plumbing beneath matters so much to the businesses depending on it.

When architecting backend systems capable of processing high-volume transactions without sacrificing speed or safety, Adesoji relies on a disciplined philosophy of architectural triage. Rather than treating every line of code as an immovable monolith, he teaches his teams to distinguish between where they can experiment quickly and where zero compromise is permitted.

"Even though a fintech system is generally a critical system, not all parts of the system are completely critical," Adesoji notes. "The first thing is identifying what parts of the system are critical, especially when you work in a startup where there is a need to move fast. For a critical part of the system, you know that you should not and cannot have a compromise. The necessary guidelines need to be in place, and as much time as needed to make relevant changes must be allocated; you cannot cut corners, and you have to be very deliberate about it."

Maintaining that fortress also requires continuous adaptation, particularly as artificial intelligence accelerates the sophistication of cyberattacks.

"With the introduction of AI into the space, threats are evolving daily, and we also see bad actors evolve daily with this," he cautions. "You need to keep upskilling, learning from other companies' experiences, and staying on top of the threats around you."

Underneath HarpFi's rigorous security posture lies a remarkably simple product philosophy: the customer should never have to feel the friction of international finance.

From Consumer Tools to a New AI Venture

Beyond enterprise banking infrastructure, Adesoji carries a restless entrepreneurial drive. Earlier in his career, he co-founded and built consumer-facing tools including Inga, a centralised bookmarking application, and Rivva, an AI-powered productivity app designed to schedule tasks around a user's fluctuating energy levels.

While Inga and Rivva have concluded their active development cycles, Adesoji is now channeling those product lessons into a new AI venture called Keona, an intelligent customer assistant built for websites — a product category that has drawn a wave of startup activity as businesses automate front-line support. Moving between the heavily regulated world of financial infrastructure and the fluid, experimental realm of AI product development requires deliberate mental calibration.

"Because most of my experience has come from a highly critical and sensitive background, I try as much as possible not to over-complicate non-financial products with all of the rigidity around security that comes with financial products," Adesoji explains. "However, even with AI products, we still have to deal with sensitive customer information that must be treated correctly. While there may not yet be as many regulatory bodies as we have in the fintech space, we still owe it to our customers to handle their data correctly and ensure how we interact with AI is safe. I balance both by taking pieces of the security mindset from my fintech experience and adapting them to the realities of AI while still innovating and moving fast."

The CTO Playbook and Shaping the Next Generation

Transitioning from a lead backend engineer writing scalable code to a Chief Technology Officer building scalable teams has required Adesoji to master human alignment alongside system architecture. For him, executive technical leadership comes down to clarity, accountability, and safe empowerment.

"From a leadership standpoint, my biggest lesson has been ensuring that expectations are set and that everyone on the team is aware of and aligned with those expectations," he reflects. "It is also about ensuring everyone has the relevant tools and guidelines needed to work effectively. Thanks to the era of AI, we can leverage technology to move a bit faster, and having those guardrails ensures that everyone is responsible for building things right while taking out complexities."

That same dedication to empowering others defines Adesoji's work outside the office. As an active mentor with initiatives including The Curve, Code Your Future (CYF) — a nonprofit that trains refugees and other disadvantaged learners for careers in software — and ADPList, an open global platform connecting mentors and mentees, he invests heavily in emerging software engineers, a passion rooted in how his own career began.

"Community impact is quite important to me because that is where I started from," Adesoji shares. "I started my career in tech through an IBM community program at my university, and without that opportunity, my progress might have been delayed, or I might never have dabbled in tech at all. Giving back to ensure other people coming up have that opportunity interests me so much, and interacting with volunteers and mentees has also been a learning avenue for me."

Observing the current wave of entry-level developers, however, Adesoji notices a recurring blind spot: an over-reliance on generative AI at the expense of core engineering principles.

"While AI has fundamentally changed how software and systems are built, it does not take away the need to have a solid foundation in software engineering," he advises. "Software is beyond just the code; there are many more parts to building reliable software. Do not cut corners in your learning or leverage AI blindly. Ensure that you are grounded in the basics and the fundamentals; that, alongside AI, is what will give you superpowers and a competitive edge."

Stablecoins and the Next Decade of Global Business Banking

Looking ahead to the next decade, Adesoji is particularly excited by the institutional convergence of traditional fintech and blockchain rails, specifically the mainstream adoption of stablecoins to solve cross-border liquidity bottlenecks.

The interest is grounded in a structural pain point: cross-border business payments have long traversed chains of correspondent banks and local clearing systems, adding settlement time and cost, while stablecoins — blockchain tokens designed to track the value of a reference currency — aim to compress that journey by settling transfers directly on shared blockchain rails.

"One very exciting shift is the adoption of stablecoins," he observes. "We can now see global companies like Stripe adopting it and playing in this space. Blockchain and stablecoins generally help ease the movement of money around the world, and I am looking forward to what fintech and finance companies will build around this."

Whether reflecting on the foundational payment rails he helped build at Kora or the borderless business banking suite he now leads at HarpFi, Adesoji measures his career not merely by system uptime but by human and economic utility.

"Seeing customers use the products we build day to day and hearing their feedback is something I am definitely proud to be part of," Adesoji concludes. "Ultimately, I want to be remembered for building impactful products that transcend time and for contributing my quota to helping people grow in the tech community."

This article is based on a founder spotlight originally published by TechNext24.