The pmgsh tool can be used to access the Proxmox Mail Gateway API via the command line.
Examples
List entries:
# pmgsh ls /
Call the GET method on a specific API path:
# pmgsh get /version
View current mail configuration:
# pmgsh get /config/mail
Get help for a specific path:
# pmgsh help /config/mail -v
Disable option spf in /config/mail
# pmgsh set /config/mail -spf 0
Delete spf setting from /config/mail
# pmgsh set /config/mail -delete spf