What is User Experience (UX)? What is a User Interface (UI)?

What is User Experience (UX)?

User experience (UX) is a standardised term that describes the experience of users of a product or service. UX is also closely linked to customer experience or even a part of it.

User experience design (UX design) is defined in DIN EN ISO 9241. According to SEO expert Ryte, UX design is the methodical assessment of the user experience, which usually happens subconsciously while someone uses a product or a service. In general, the assessment is based on all aspects of the customer journey where users interact. Usually, the user experience is preceded by a prior experience, a need or an expectation. On the internet, criteria can be accessibility, beauty and usability.

  • Accessibility: Responsive design, availability of service, loading times

  • Aesthetics/beauty: Subjective charm of the design/layout of the website or app

  • Usability: Concise information structure, effectiveness of functionality, unambiguousness of content, cross-platform (digital experience platform)

There are as many possible variables in user experience design as there are individual users’ needs. No matter what you expect when you use a product or service, in the end, the user experience stands for high subjective expectations from customers in terms of applications that add value and work without a hitch (utility).

Assessing User Experience

There are different methods to assess the user experience on a website or application, based on scope and type of product. At the beginning of a project, we recommend assessing the current status of the existing solution in an expert review – assuming the necessary information is available and it is not a complete greenfield project where you start from scratch. In both cases, however, it is possible to identify weaknesses and initial quick wins in early checks.

Example of Website UX Testing

Prototype: During the implementation project, experts in the different fields do user tests with the prototype. Both the structure of the website as a wireframe and design prototypes can be used in this stage. The latter represents the user interface (see below) and selects specific functionalities. The more concrete and more similar to the final product the prototype gets, the more realistic the test results become.

Operation: If a project is already up and running, testing is done on a live system. Experts draw initial conclusions from conventional data tracking and A/B testing. The challenge lies in the interpretation of underlying data sets. Heatmaps are another possibility: A heat map visualises areas that draw the most attention from users. Recorded user sessions that focus specifically on the needs of the target group serve a similar purpose.

UX Design and the Special Status of Usability

Usability plays a major role in the user experience. According to the ISO norm mentioned above, it is the “extent to which a product can be utilised by users in a particular context to achieve specific goals effectively, efficiently and satisfactorily.” It is applied wherever there is an interface between humans and machines/technology (human-machine interaction). According to Marc Hassenzahl, professor at the Institute for Business Information Systems at the University of Siegen, Germany, “We experience products/services positively when during their use, a person’s psychological needs are met”. Or, in short: “We don’t notice usability when it’s good, but we do when it’s bad.”

What is a User Interface (UI)?

The user interface is the interface at which the human-machine interaction described above takes place (also the frontend). Humans use this interface to control certain elements of the machine. Users also need a user interface to interpret the machine’s feedback faster. So, strictly speaking, the UI is the platform on which humans and machines exchange information and interact. This type of communication requires physical and logical components, hardware and software.

Just as there are different aspects to assess user experience, there are also different UIs. The most common interfaces are the graphical user interface (GUI – see also Frontend/Backend) and the web user interface (WUI). The GUI is a graphical interface that is activated via a mouse, touchpad and keyboard. The result is projected onto a monitor by a computer using a graphics card. The WUI works in a similar way. It displays web-based content. The difference is that the web-based UI generates content exclusively via the internet and interaction is also triggered via the internet. Users can view results and entries in their browsers on different types of devices.

UI and Cognitive, Systems or Software Ergonomics

To guide users through the different surfaces, user interface design needs to be ergonomic and user-friendly. UI designers rely on various scientific disciplines to look specifically into digital ergonomics:

  • Cognitive ergonomics – Researches the information environment and sets standards for how humans can cooperate or interact with technical systems.

  • Systems ergonomics – Relies on expert opinions to set standards and design systems in a way that all components harmonise and interact suitably, functionally, practically and understandably with users.

  • Software ergonomics – Looks into the usability of interactive software. Based on recommendations, UI designers try to adapt the UI to the knowledge and habits of users (target group-centric development.


  • Psychological heuristics – heuristic approaches are strategies people use to make decisions in a limited time and/or with limited knowledge – with or without tools. These heuristics can be used as principles to make UIs more user-friendly.

Advantages of Well-Orchestrated UX/UX/Usability

The user experience already begins with the idea of using a product or service, before the actual use. Usability is what happens during use. If they are orchestrated well, this can have a host of advantages.

  • Customer satisfaction with products

  • Insights – what do customers want

  • Promotion of product development

  • Reduced support and training costs (intuitive use)

  • Increased sales revenue (popularity, usefulness)

  • Quality of products

  • Extension of the product lifecycle

Contact for your Digital Solution with Unic

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Are you keen too discuss your digital tasks with us? We would be happy to exchange ideas with you.

Jörg Nölke
Gerrit Taaks
Gerrit Taaks

Contact for your Digital Solution

Book an appointment

Are you keen to talk about your next project? We will be happy exchange ideas with you.

Melanie Klühe
Melanie Klühe
Stefanie Berger
Stefanie Berger
Philippe Surber
Philippe Surber
Stephan Handschin
Stephan Handschin