The Engineering Challenge
Over the course of my QA career, I've spent most of my time working on systems where a small defect can have real financial consequences: digital banking platforms, payment gateways, mobile wallets, lending and savings products, insurance, corporate card platforms, and financial reconciliation services used across Africa and Europe.
Unlike many applications where an issue might cause an inconvenience, financial platforms require every calculation, transaction, and integration to behave exactly as expected. The challenge has always been to understand how money actually moves through a system, identify the edge cases before they reach production, and verify that every transaction is processed correctly from start to finish, not just that the UI reports success.
The Solution
At Cellulant, I tested multi-market, multi-currency payment flows and reconciliation logic, including PSP integrations and the Bank of Agriculture's digital banking platform in Nigeria, validating transaction flows and banking operations across different services.
At JUMO, I tested lending, savings, insurance, and customer eligibility logic, verifying financial calculations, repayment schedules, product rules, payout processes, and data consistency across services supporting millions of customers in Africa and Europe.
At Pleo, I worked on corporate card payments, transaction processing, expense categorisation, and collaboration features that allow multiple users to manage company spending accurately.
Alongside fintech, I've also tested SaaS platforms and design products, giving me experience with different user journeys while applying the same disciplined approach to quality, reliability, and customer experience.
Technical Decisions
Most of this work involved much more than validating the user interface. I regularly used Postman to test APIs directly, SQL to verify data at the database level, and observability tools such as Grafana to investigate production behaviour and monitor distributed systems. Rather than assuming a transaction completed because the interface said it did, I traced requests through the services involved and confirmed the underlying data matched the expected outcome.
Working closely with developers, product managers, and business teams also shaped how I approach test design: understanding the business rules behind a feature, not just its acceptance criteria, is usually what surfaces the edge case that would otherwise reach production.
Measurable Outcome
Testing financial systems has reinforced the value of precision, curiosity, and attention to detail, whether I'm validating a payment, a lending decision, or a reconciliation process. The consistent outcome across these roles was catching data-integrity and calculation issues before they reached customers, by verifying at the API and database level instead of trusting the interface.
That same rigor now extends to how I evaluate AI-assisted testing and AI-powered applications: the tools change, but a thoughtful, systems-level testing mindset is the most valuable skill I bring to any product.