Backendless does not support the concept of default roles. There are system–level roles (for example, AuthenticatedUser, NotAuthenticatedUser, FacebookUser, etc) and there are custom (user-defined) roles. Custom roles have a different privilege order which Backendless uses when it makes a decision whether an API operation can or cannot continue. Currently you cannot make one custom role more "important" than others.
How can I make my custom role a default one?
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