About: a German company Bonial developed kaufDa – B2C app with over 3M monthly users that highlights the best local sales online, allows to search brochures of local retailers, and find stores near them.

Role: Product Designer (generalist), in collaboration with the User Researcher and Junior UX/UI Designer, Copy-Writer, engineers, PM, and PO.

Duration: 4 month


  • Product (UX/UI) Design
  • Design Strategy
  • Data Analysis & Synthesis
  • UX Research
  • Rapid Prototyping


there’s no way to interact with product deals that are available in the brochures.

Strategy and Approach

Addressed user needs by appealing to personas

Being the 8-years old product kaufDa had users of diverse ages, gender, and social statuses. German expert consumers had high habitual behavior patterns. So, innovations or changes in the product were perceived negatively which was the biggest challenge to face. The strongest user demands were exploring the deals close to the user’s location, full-screen brochure browsing, ability to see the latest deals from all retailers.

Benchmark analysis and paper prototype tests

As a Product Designer, I developed a strategy to tackle the problem and distributed it among the team. Together with the user researcher, we started with exploring a market competition. We discovered interesting opportunities, which we wanted to test with our users. After printing paper prototypes we asked users to gather their own feed which would also include new content type – product deals. In this way, we found out users’ personalization preferences and information architecture hierarchy. The results turned out to be mixed, so I initiated an additional internal workshop to make a decision on which variation we choose to move forward.

Introducing new content type variations

Co-organized Design Sprint

After sharing our previous research findings, collaboratively during the 3-days Design Sprint, we came up with the hypothesis on how to appeal to the novice and power users when introducing a new content type that I and a junior designer framed in the high-fidelity prototype.

Made prototypes, tested and designed UI

After rapid prototyping, we did a quick gorilla testing, iterated the designs, and came up with a final version. As a result, we introduced a tooltip (1) on the new app updates; added product categories (2,3), when selecting favorites; showed product deals on the homescreen (4), and…

…integrated view by product (5,6) in the brochure viewer; created product details view (7,8) with the option to save and share a product. Together with the PO, we prepared a quantitative research plan for the data team to gather more objective insights on user interaction with the updates we launched. As a result, since 2018, the number of monthly users grew from 3 to 8 million.

Key learnings

  • Testing personal user preferences trough qualitative research brings more subjective results.
  • Include text indicators to the icons which are not intuitive.
    Implement commonly used interactions.
  • Do not overload the interface with learning tips leave a space for the users to explore.
  • Use one or two major updates at a time to avoid a cognitive load.
  • Rely on analytical data collected after 2-3 months when significant interface changes where released.

Things I’d change

  • Make possible viewing the brochures from the other retailers without accessing the brochure viewer screen.
  • Use more simple interactions.
  • Launch one major change at a time instead of overwhelming the user with many interface updates at once.
  • Add “Expire soon” for the product deals.
  • Add a reminder for “Expire soon” deals.