Borg is a deduplicating and compressing backup program. Optionally, it also supports authenticated encryption. It was forked from the attic backup program.

The main goal of Borg is to provide an efficient and secure way to backup data. The data deduplication technique used makes Borg suitable for daily backups since only the changes are stored. The authenticated encryption makes it suitable for backups to not fully trusted targets.

It can push backups to remote repositories accessed via ssh. A client pushing a backup invokes "borg serve" on the repository host. It is possible to restrict the ssh key to "borg serve" using the authorized_keys command= clause.

Please note that the server and the client should be on the same version of borgbackup. Using different versions of borgbackup on client and server might result in 'incompatible API version' error messages and a non-working backup.

While there is no direct operations mode for pull-type backups, you can configure the backup target in append-only mode, preventing the backup source from deleting or altering previous backups.