Since 1994, Bernhard Prümper, Managing Director of Coolgrey User Interface Design GmbH, and his team have been developing functional user interfaces and web applications for renowned companies such as

Bosch, Blaupunkt, DaimlerChrysler, Deutsche Bahn, Dresdner Bank, Siemens, Sony, Lufthansa and many others.

Our comprehensive range of services is based on this background of experience which we offer our customers in transparent development processes.

Various projects have been honored with the following design awards:


Service Range

For an optimum project result the planning, implementation and operations must work together. The team of Coolgrey, therefore covers the entire range of services:

We offer our customers comprehensive services from the analysis, concept, design and production up to usability testing and technical documentation.

We ensure efficient functionality of your application and compliance with your corporate identity guidelines as well as an optimum feasibility in programming.

Regarding the ergonomic requirements, we work, if requested, in accordance with DIN EN ISO 9241 and DIN EN ISO 13407.


The main areas of our work are:

• Analysis of established software and business requirements

• Coordination of business processes and IT applications

• Stucturing of contents

• Mapping of business processes

• Definition of work processes

• Design of dialog control

• Usability testing

• Graphical implementation of the conception

• Application or development of corporate design guidelines

• Styleguide development

• Production of the frontend

• Technical documentation