Usability testing is a method of evaluating a product, service or application by real users in a controlled environment. The aim of these tests is to find out how simple and intuitive a system is for the end user. As a rule, specific tasks are set for the user to perform with the system under test, while observers document the user's behaviour and reactions.

Usability tests are an integral part of the user-centred design process and play an important role in product development, especially in the area of software and web development. They can be carried out in various development phases and in different forms, such as formative or summative tests, remote or laboratory tests.

Formative usability tests are often carried out in the early phases of product development and are used to identify concept errors and highlight opportunities for improvement. Summative usability tests, on the other hand, are usually carried out after a product has been finalised and are used for the final evaluation.

A well-conducted usability test provides valuable insights into where users encounter problems and which aspects of the design can be improved. This not only increases end-user satisfaction and efficiency, but often also reduces support and training costs. Overall, usability testing helps to develop a marketable and competitive product.