In recent years, the e-scooter has gained exceptional worldwide adoption, and their hybrid vehicle design has placed them in a legislative void. To this end, many cities are developing local regulations to govern and follow-up e-scooter operations within their jurisdiction. As e-scooters are equipped with hardware like SIM cards, GPS sensors, and accelerometers, the vehicles can both collect and act on digital information. Increasingly, cities thus draw on these capabilities using the Mobility Data Specification (MDS) as a soft digital infrastructure to e.g., express local regulations and collect operator data for compliance purposes. This paper uses interview data from European and U.S. cities, e-scooter operators, and systems integrators to provide an overview of the history and components of MDS. The paper also presents cities’ current uses and emerging challenges regarding using MDS for regulation, compliance monitoring, as well as data analytics for physical infrastructure planning.