trigger workflow when a contact unsubscribed from email campaigns totally

trigger workflow when a contact unsubscribed from email campaigns totally

hi,

is there any way i could set up workflow when a contact unsubscribed from email campaigns totally, so i can call a webhook for that particular user? and what field would that be for the contact? also what api can be called to zoho to update that field, i.e. unsubscribe users from email marketing?

thanks