Increasing amount of distributed energy resources necessitates more flexibility at the distribution network level. One option to attain this flexibility is by aggregation of these resources within microgrids and further supervisory control of the latter in active network management. Among other reasons preventing their realization, these flexibility services lack standardized information and communication technology solution. This study assesses the required communication, information, and functional competences for such services and describes them by means of a use case modeling on smart grid architecture model planes. Specifically, the paper focuses on an information exchange built on the basis of web application programming interface called Smart API. The results of the study present a smart grid architecture that would enable real-time control of microgrid resources in active network management through flexibility market services.