In one embodiments, a method for authorizing access for an application programming interface (API) client or API client device to data of one or more data models of one or more smart devices includes retrieving a number of access tokens from an authorization server, and providing, via a single connection, the number of access tokens in a request made by the API client or the API client device to the API, wherein the number of access tokens are used to verify access rights of the API client or the API client device to read data for a number of users associated with the one or more data models of the one or more smart devices.