Actions and Triggers are supported by Backup Client. There are four actions and two triggers available.

Actions:

• Backup website and database

  This action is the equivalent of pressing the `Backup Website` button.

• Backup database

  This action is the equivalent of pressing the `Backup Database` button.

• Remove extra website backups

  This action is the equivalent of cron removing extra website backups.

• Remove extra database dumps

  This action is the equivalent of cron removing extra database backups.

Triggers:

• A website backup is made

• A database backup is made

Hooks and Alters:
$parameters is a keyed array of all the configuration options and values of the related function.

• A website backup has just been completed.

   module_invoke_all('backup_client', 'tar_backup', $parameters);

• A database backup is has just been completed.

   module_invoke_all('backup_client', 'mysqldump', $parameters);

• The list of files to exclude has been built.

   drupal_alter('backup_client_excluded_files', $excluded_files, $parameters);

• The list of files to include has been built.

   drupal_alter('backup_client_filelist', $filelist,  $parameters);

• The list of tables for a database backup is about to be returned.

   drupal_alter('backup_client_mysql_tables', $tables, $source);

More Info:
Drupal handbook page on triggers
Drupal handbook page on actions