Parts of a Realtime Application
Realtime Document A single unit of data that can be shared and collaborated on.
Realtime Model The contents of a Realtime Document. This is where you store your application’s data. The Realtime API provides easy methods for reading and writing this data. See Build a data model.
Collaborator A user who can view or edit a document.
Drive App In order to enable collaboration, your application must be a Drive application. This authorizes you to read and write to a user’s Drive and integrate with the Drive UI. An app is defined by an entry in the Google Developer’s Console with the Drive API Enabled. See Create a Realtime app
Drive File A file stored in Google Drive. A Realtime document can be attached to a file in order to enable collaboration. Files are created and shared via the Drive API. See Drive Files.