In a 5G era when the cellular network needs to support not just connectivity, but a fully distributed cloud and apps platform, APIs (application programming interfaces) will be as important to interoperability as radio standards. Perhaps it is no wonder, then, that the 3GPP has seized back the responsibility for defining standards for northbound APIs to connect the cellular network with applications servers. In 2008, the standards body transferred its efforts on northbound APIs, in the shape of the Open Service Architecture API, to the Open Mobile Alliance (OMA). Since then, the OMA has developed standardized interfaces between mobile networks and the service infrastructure, though these are increasingly augmented, depending on the use case and network, by APIs from other…