Does CubeBackup work through official Google APIs or through some other method?
Google APIs only
All communication with Google’s servers is done through official Google APIs, including Google Drive API, Gmail API, Google Workspace Admin SDK, Google Calendar API, Google People API, and Google Sites API.
All communication is strictly between your backup server and the Google cloud using HTTPS protocol. No data is routed through our servers or any third party.
Local SQLite files are used to track folder and file revision histories, so that only changes to your files are downloaded, much like GIT.