Behind the Scenes: Building FIQ Personal

Building a personal finance app is deceptively complex. On the surface, it looks like a transaction list with some charts. Under the hood, it is a real-time data pipeline connected to banking APIs, a rules engine for categorisation and budgeting, an amortisation calculator for debt plans, a projection engine for goals and cashflow, and an educational content platform, all of which need to work together seamlessly and handle sensitive financial data with appropriate care.

We chose our technical stack with long-term maintainability and performance in mind. The mobile app is built with modern cross-platform frameworks that let us ship on iOS and Android from a single codebase without sacrificing native feel. The backend runs on scalable cloud infrastructure with event-driven architecture so that bank feed updates, budget recalculations, and notification triggers happen asynchronously without blocking the user interface.

The hardest engineering problems were not where we expected them. Bank feed reconciliation across dozens of different UK banks with inconsistent data formats was significantly more complex than anticipated. Building a budget engine that supports multiple methodologies while keeping the user interface simple required careful abstraction. And ensuring that every calculation, from tax provisioning to debt payoff projections, is accurate to the penny across edge cases is the kind of work that is invisible when it goes right and very visible when it goes wrong.