From a powerful user experience

Toward innovating with an app

With a unique Dundle feel

tech stack

Used tools & technologies

The popular BLoC pattern for state management, clean architecture and clean code principles and a combination of back-end customization and Supabase (Back-end as a Service).

  • Flutter
  • Bloc library
  • Sentry
  • Supabase
  • Firebase
  • Google Analytics
  • Jira
  • BLoC

In the competitive market of digital gift cards, user experience is key. KORSIT’s brand new app had to be fast and beautiful. Includes floating islands and smooth animations in the loyalty program with gaming features.

With more than eighty payment methods tailored to 23 countries, KORSIT is a major player in the international market. From its webshop Dundle, KORSIT serves private customers who want to buy digital gift cards. “Our user experience has always been our strength,” says Ricardo Broeders, Board Member Operations at KORSIT. “We wanted to continue innovating on that with an app that allows us to engage customers.”



One of the ways KORSIT differentiates itself is its comprehensive loyalty program, Dundle World. Customers save Dundle coins that they can spend in this online world with gaming-like features. Ricardo: “The developers could go all out on that. It had to look great and you had to be able to swipe from island to island with lots of animations and transitions. It was cool to see how Dundle World was created in the app and how much more life there is now compared to the version on the website because of the animations and interaction.” In terms of the front end, the floating islands made it nice and challenging. Duco: “In the background it’s not so bad, there it’s mainly a matter of getting some data and showing data. Although there was also a challenge there, namely speed. Because this is a product with changing stock and prices, you can’t store anything locally. So you have to keep retrieving the latest information at lightning speed.”



An important condition was that the app be available in the Google Playstore and the Appstore. Team Rockstars therefore introduced the relatively new framework Flutter to KORSIT’s developers. “With Flutter, you can build apps for different platforms with one code base,” said Duco Fronik, mobile developer at Team Rockstars. “Flutter has built a layer on top of the platform-specific APIs of Android and iOS, among others, so you can write code for all platforms at once. So: only build once, test once, fix bugs once. That saves a lot of time, allowing you to go to market very quickly. Moreover, Flutter offers all components to completely customize the UI. That makes the framework eminently suitable for a branded experience: you can determine pixel by pixel what the app will look like and are much less bound to standard components than when you develop specifically for iOS or Android. As a result, the final product feels unique.”

Running in the background are Firebase and Supabase (both Backend as a Service, including for push notifications and user authentication). Sentry and Google Analytics are used for error detection and analysis. Within Flutter, BLoC (Business Logic Components) was used as a state management solution combined with clean architecture to maintain rapid development. Jira from Atlassian is used to organize all activities and manage the backlog.



Team Rockstars began as an external team, to deliver a Minimum Viable Product after several months. This was so successful that cooperation intensified. Ricardo: “We had never worked with an external team before, so I was worried beforehand. Would it click? But it was immediately clear: This works. Our cultures fit together perfectly. That made it a very cool process.” The collaboration was also a treat for the Rockstars. Duco: “KORSIT is just a really nice company. I always go for a game of pool when I’m there and on Fridays there’s a get-together. The vibe at KORSIT is just as cool as it is with us. That makes it doubly fun to work for Team Rockstars.”

Ricardo is especially appreciative of how quickly the Rockstars were operational. “That is truly distinctive. As a result, we were able to reap the benefits of the collaboration very quickly. After every brainstorm, new features were finished before I knew it.” Keeping that fast pace is not a given. Duco: “When you just start a project, there is still relatively little code. But that is becoming more and more. The ratio of reading code versus writing code is ten to one. So the more code there is, the more you have to read. You don’t avoid working a little slower as a result, but we still go very fast. That’s only possible if you organize the code well, don’t write more than necessary and follow clean code principles. Then the code base does grow, but you can still make changes and add new features quickly.”



Meanwhile, the app is running as a thriving sales channel. “Without really running a campaign, after just a few months we are already at just under 30,000 downloads from 12 countries,” Ricardo says. “Our main goal was to get repeat customers to buy through the app, and we’re seeing that happen very fast now. Those numbers are definitely going to continue to grow. And if you look at the revenue compared to the website, the difference is very big. We really have an additional tool in our hands to engage customers. And the app looks great. Thanks to the Rockstars’ input on looks, functionalities and transitions, the app feels very light. Those transitions came in very nicely and everything works lightning fast.”


Final phase of the app project is the transfer to the developers of KORSIT. Ricardo: “It wasn’t just about developing the app, but also about knowledge transfer so that our developers can move forward with it.” Even after this, however, the farewell is not final. “This good experience made us realize that we want more Rockstars for content, backend and project management. And really not just because the market is scarce. The collaboration went so smoothly and we can use their expertise so well that we want to expand the partnership. Soon, another new Rockstar will start.”

“Because of this good experience, we found out that we want more Rockstars for content, backend and project management. “

Ricardo Broeders, Board Member Operations at Korsit