The BCF REST API allows you to connect with Solibri, Bricscad and Vrex to manage your projects. This includes not only topics but also viewpoints, files, documents, and so on.
By definition, any BCF API implementation is project-based and there is no concept of hubs in the specification. On the other hand, BIM Track projects are always stored within a hub, in a specific region. This requires anyone who wants to call the BCF API to know in advance which region to target. Users can access the exact URL to use for a project from the Integrations page.