Micro-credentials research, which includes digital badges, is a relatively new field of study that seeks to inform the implementation, portability and sustainability of the ecology of meaningful delivery. This paper reviews literature relevant to understanding connections between universities' intent to offer micro-credentials and the environment that is needed to do so. From this integrated study, the paper distils a number of core concerns and identifies some gaps in the literature. One of its primary goals is to clear the ground for the construction of a technical model of micro-credentialing implementation that can be used by the various stakeholders involved in the design and evaluation of new micro-awards. A closely related goal is to help those participating in micro-credentialing research to locate and understand each other's contributions, as fragmentation in research related to micro-credentials makes progress in the field slow. Hence, this review draws together research in the field to identify research foci and gaps, and then also capture some work by micro-credentialing researchers that directly attempts to model the main relationships in the field. The paper ends with a summary of implications for practice, especially for the Australasian higher education context.