The ever-increasing customer demand for use casespecific B2B software puts platform owners into a challenging situation where integrating a B2B app store into their digital platform becomes a necessity to manage the dynamics of software platform ecosystems. However, platform owners face uncertainty and experiment, while platform ecosystem research provides limited guidance for specific B2B app store governance. Closing this gap, we use multiple case studies and develop three taxonomies for architecture, control mechanisms, and demand generation to provide an overview of the solution space for B2B app store governance. We further derive three robust B2B app store governance types: platform play, transaction channel, and community platform. This paper enriches the B2C-driven and core-offering related research on digital platform governance with tangible B2B app store governance dimensions and types. We envision to guide practitioners in identifying and selecting governance characteristics to remain competitive and provide innovation for their B2B app stores.