Health-Tech Booking Platform

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.

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.

The project demonstrated how deep UX research and a focus on user pain points can radically change a product, even one with a complex technical legacy.

The work began with a deep dive into the existing system. The client provided a detailed technical specification, the web version's architecture, and the results of their own research (CJM). The Linkup ST team took on the role of a product team, breaking the system down "into atoms" to understand the logic of every module.

The primary challenge was the immutable backend. This meant creating a modern, lightweight, and intuitive interface that had to run on an "old engine" with complex, rigid logic built up over years.

Analysis revealed several critical pain points faced by clients: Limit Settings was the most problematic area — the functionality in the web version was so convoluted that users literally struggled to set the necessary restrictions for drivers. Financial anxiety was common, as businesses were losing money due to expired fuel coupons because the system lacked any notification features. Payments were cumbersome, since invoicing and paying through third-party services was protracted and contained many unnecessary steps.

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.

With the three user segments defined, the team designed dedicated flows for each — surfacing only the balances, limits, and actions relevant to how that business actually uses fuel resources, instead of forcing everyone through one generic interface.

Limit Settings were rebuilt around plain-language rules and sensible defaults, replacing the tangled web-version configuration with a guided, step-by-step flow that fleet managers could complete in minutes.

To resolve financial anxiety, the app introduced proactive push notifications for expiring coupons and low balances, giving businesses time to act before money was lost.

The payment and invoicing flow was collapsed from a multi-step, third-party process into a streamlined in-app experience, cutting unnecessary steps while keeping the rigid backend logic fully intact behind the scenes.

The redesigned mobile experience turned a desktop-only, back-office tool into something managers and drivers reach for on the go. Drop-offs during setup fell sharply, task success rates climbed, and payments that once took multiple sessions to complete were finished in a fraction of the time.

More importantly, the segmented approach meant every user — whether managing a single fuel card or an entire mixed fleet — found an experience tailored to how they actually work, proving that even the most rigid legacy systems can be made to feel effortless.