DataSync (User) introduction
Users are a built-in DataSync entity class representing the people or devices in your app.
Note: For more information, refer to Users, channels, and memberships. These endpoints are the DataSync successor to the App Context user endpoints, which remain available.
Authorization
Access Manager must be enabled on the keyset, and every DataSync request must carry exactly one credential: either an Access Manager token in auth, or a request signature. There is no anonymous access.
Supplying neither fails with 401 (DS-0203, UNAUTHENTICATED). Supplying both fails with 403 (DS-0201, ACCESS_DENIED), as does calling DataSync on a keyset without Access Manager enabled.
Refer to DataSync access control.