Zoltan Gocza

Numbrs AG (2013–)
Head of UX


At Numbrs, we set out to redefine banking. Our multi-banking mobile app became the #1 finance app on the German App Store with more than 700.000 downloads in the first 8 months.

Leading the UX team

I built a UX team of 4 truly awesome designers that is in the forefront of defining product strategy and designing new features and improvements.

Product design

I designed several of the core features of our app for both iOS and Android. The design process I follow is highly iterative, working very closely with management and the cross-functional teams. I use research, validation and customer feedback to inform design decisions.

Due to my NDA, I can only share a very limited selection of designs.

Selected project: Send money

I designed the current send money flow for both iOS and Android, a project that resulted in a huge lift in engagement, and received very positive user feedback.

Here's the final interaction:


My goals were to improve the adoption rate and to drive repeated usage.

In order to achieve the goal, Numbrs had to offer a clearly superior send money experience to other mobile banking apps. We also needed to build trust to make our users feel confident making financial transactions with a third-party app.


To guide my design process, I laid down some guiding principles:

  • Typing is a pain on mobile, always put selection over typing
  • One screen interaction over the iOS standard hub and spoke model
  • Set user expectations upfront by showing the full extent of the flow (trendy wizards wouldn't work for this purpose)
  • Put easy inputs first, bring the user quickly up to speed
  • When it comes to intelligence and smart suggestions, rather err on the side of simplicity than to make mistakes


Following my research and the concepting phase, I created the skeleton model for the feature:

I refined the flow into lo-fi wireframes first:

Lastly, I created the hi-fi wireframes and prototypes to test the flow.

Validation: usability testing

The new send money flow introduced new interaction patterns, especially by merging the flow for contact search and new contact creation. To validate the proposal, I created an interactive prototype and tested it with a handful of people. The tests (and later hard usage data) confirmed that the interaction was immediately clear to users.


The reception of the new design was very positive both in terms of user feedback and usage metrics. Both the first time and the repeated usage of send money saw a quick and sustained lift. Users trust our app for transferring money over their banks’ own apps.

Some of the feedback from the app stores (translated from German):

Sending money works like a charm – Pierre Münzenberg

Sending money is delightfully quick and easy – Volker Fleißner

The app simplifies sending money compared to the Sparkasse app – Illegret Schade

Really cool, transfers are very quick. I can only recommend – Dobou Paul

It can’t be easier. Sending money with this app is even simpler than on the computer – Julian Kutscha

I signed up in 4 minutes, then made my first money transfer. So intuitive and simple! I could rave on forever, 10-star app – Adrian Piotrowski


Have a wonderful !