The adoption of building information modelling (BIM) enables data-driven decision-making for many participants in the construction process. Building authorities are stakeholders that have not yet benefited from data integration using BIM. In many cases, parts of their processes have already improved through digitisation initiatives. Now they are on the threshold of a major digital transformation enabled by the integration of BIM into their processes. This study examines a building permit process based entirely on BIM, developed at the Vienna Building Authority in Austria. In a series of workshops with all important stakeholders, the current building permit process was captured in detail and transferred to a data-driven, BIM-based process. The study shows that the complete capture and digitisation of the building approval process not only enables the automation of traditional processes such as code compliance checks and neighbourhood hearings but also supports the introduction of innovative sub-processes such as a pre-check of BIM models and augmented reality-based hearings with neighbours (in a pilot phase). The results suggest that the developed process not only significantly increases the efficiency and transparency of building permit procedures, but also represents a decisive step towards integrating the authority into the BIM process of a building.