Backend Architecture Decisions Every Startup Should Get Right

What You Will Learn

OKKO is one of the largest fuel retailers in Ukraine, operating across B2B and B2C at national scale and covering 18–19% of the country's retail fuel market. Its Smart B2B platform is a fuel resource management ecosystem used by Ukrainian businesses to control expenses, manage fuel cards, and handle vouchers.

The platform existed only on desktop, making it unusable in dynamic, on-the-go environments where managers and drivers actually operate.

Why Inspiration Matters

This is why the Linkup ST team was tasked with more than just building a mobile app; they had to essentially reinvent the user experience while keeping the complex business logic under the hood. This case study explores how deep analysis and a focus on real user needs allowed a bulky system to be transformed into a convenient mobile tool.

Key Takeaways

• Segment users by how they actually work, not by how the backend models them.
• Simplify complex settings with plain-language rules and sensible defaults.
• Use proactive notifications to remove financial anxiety before it happens.

Analysis revealed several critical pain points faced by clients, and each one shaped a specific part of the redesign — from limit settings to payments to day-to-day navigation.

Putting It Into Practice

To find the right solutions, the team segmented users into three distinct groups, as their interaction scenarios differed cardinally: "Cards Only" users who use the fuel card like a wallet, "Coupons Only" users who work based on pre-purchasing specific volumes of fuel, and "Mixed Type" users — the most complex group, needing to see the full picture simultaneously.

This approach allowed the raw technical specs to be converted into a viable app architecture. Read more in our related case studies.