CitoSnack — Make existing vending machines more attractive

My role: My responsibilities included understanding the user, prototyping, wireframing, designing and validation

Team partner: Marcus Wild

Semester: 4

Man buys something from a vending machine


Pay quickly, easily and without contact. In almost all stores, customers can pay by card as well as with their mobile device.

However, this trend has not yet reached most vending machines. This seems outdated in our modern society. As part of our elective course “Innovation Management”, we dedicated ourselves to the task of realizing a more contemporary solution for purchase at vending machines.

Apple Pay

The Goal

With the help of an easily understandable user interface and a payment process with RFID technology, a simple and engaging interaction should be created. Because purchasing a new vending machine would be associated with high costs, we would like to offer our customers a retrofit kit.

The retrofit kit should be able to be implemented in existing machines and upgrade them inexpensively.

This saves costs and resources. The option of paying in cash should continue to exist.


Roadmap von dem Projekt CitoSnack


What is important to Germans when paying? What is the most popular form of payment? In addition to the user needs, we also analyzed the market conditions in different countries. Here is a brief insight:

User Needs

Indispensable for payment(%)



Clear overview


Easy to use


Fast payment process

What is easier?

Is a simple payment method(%)



Debit card


Credit card



When asked about the important properties of a means of payment, security, a good overview, ease of use and the fast payment process were rated as essential.

26% of those surveyed find paying by credit card easy. Paying with debit card and cash is rated significantly better. It is noticeable that paying in cash is perceived as easier than generally paying with a card. There seems to be a lot of room for improvement in the card purchase process.

There are over 15 million vending machines around the world, of which over 550,000 are in Germany. With a total turnover of 2.9 billion euros in 2019, Germany leads the list of the countries with the highest turnover by a large margin.

Our research showed great potential in this market and some opportunities for improvement. We also quickly realized that we would need a competent partner company to convert the machines.


With the help of the persona, the main user groups should be described and their behavior should be represented on the basis of various characteristics. During the creation, we used the knowledge gathered from the analysis phase and thus formed meaningful personas.

Persona of a card payer
Persona of a cash payer

Paper Prototyping

Sketches interface development

Show and test initial ideas quickly, cheaply and easily. Paper prototyping is a powerful tool for gathering first insights.

After we created our prototype, we carried out several "Thinking Aloud Tests" and received important knowledge at a very early stage of the project.

We carried out tests in different phases in order to continuously improve the product and offer the user the best possible usability.

Low Fidelity Wireframing

Wireframes interface development


Moodbard for the high fidelity design

The aim here was to define and show the mood and color of our product. Describing the character of an interface in words can be very difficult. That is why a mood board is a powerful tool for presenting the appearance of a project.

The Result

After we had completed some important steps within the development phase and clarified questions regarding structure, usability and color, we brought our work and findings together in the screen design.

The screen are represented on a vandal-proof display which is attached directly to a vending machine.

CitoSnack Screendesign Gallery

Our Added Value

When developing our product, we deliberately went through many loops in order to create a well thought through and simple interaction.

We contact various potential partner companies, calculated prices and looked at the product from different angles.

Item Overview Screendesign from CitoSnack
Card icon

Card payment

Pay contactless with your smartphone or with your card. We support various payment options.

Cash icon

Cash payment

Only cash with you? No problem. Pay as it suits you best!

Touch icon


Do I put in the money first and then choose the product, or is it the other way around? There are no such questions with us. Enjoy a simple and self-explanatory interaction.

Plus icon

Simply more

With us you don't have to start a new purchase for every item. Buy several items together and pay conveniently as you want.

Beautify icon

New by retrofitting

Vending machine operators do not have to buy a new machine. CitoSnack saves costs and protects the environment.

Item Overview Screendesign from CitoSnack
Article overview
Shopping Cart Screendesign from CitoSnack
Shopping cart
Payment Overview Screendesign from CitoSnack
Choice of payment method
Pay with card Screendesign from CitoSnack
Card payment
Curchase completed Screendesign from CitoSnack
Purchase completed

During the high fidelity prototyping, we regularly adjusted the color composition, layout, shading, symbolism and a few other design elements.

After the changes, we obtained further user feedback and developed a user-centered user interface over the course of the entire screen design process.


How can this project continue? In addition to a new interaction, there are various other topics and goals that can be carried out.

If the interface has been realized and the retrofit kit implemented, the next goal can be to network machines. Vending machines could be helpful for refill services and provide information about current stocks and optimal delivery routes.

Implementation in Google Maps could be a real added value for customers. The "Internet of Things" represents the future of vending machines and enables new interaction possibilities in our project.