In software development, it is long been understood that usability testing is a prerequisite to intuitive and usable user interfaces. But there is still no known method to integrate usability tests early into the development process of software, especially if it is meant to be used by specific users. The literature describes several specialist techniques to measure the usability and to set up usability experiments, but all of these involve recruiting specific users for testing, and thus risking a shortcoming of usability tests throughout the development process. This work introduce a new usability testing technique, that allows early and continuous usability testing, without the need to recruit expert users. The approach of jobbased usability testing is to iteratively test and improve prototypes for software that is meant to be used by specific users to perform specific tasks and achieve specific goals, and still can be tested with average users. This new approach is expected to dramatically reduce the cost of recruiting participants for testing throughout software development projects, and hence make continuous usability testing viable.