A data middle-platform (DM) is expected to provide innovative digital data services to deliver data value. It allows separation of the fundamental technical supporting capabilities from the business-related services. The main purpose of a DM is to aggregate and manage cross-domain data into services. For Internet of things (IoT) and smart sustainable cities (SSC), a DM aims at providing common data services that can be reused in diverse application domains by governments, enterprises, organizations and individuals.