Represents the original provenance of a subscriber. This value is not exposed to subscribers; it's only used for internal tracking purposes and governs some of the behavior of the subscriber (i.e. whether or not to require double opt-in.)
This subscriber was added by a member of Buttondown support staff.
Subscriber created by API.
This subscriber joined via Carrd.
This subscriber joined via commenting on an email.
This subscriber subscribed via an embedded form.
This subscriber subscribed via a Buttondown form.
This subscriber was imported from another service.
This subscriber subscribed to your newsletter of their own volition.
This subscriber joined via Memberful.
This subscriber joined via Patreon.
This subscriber joined via Stripe.
This subscriber was added by a user with write permissions for subscribers within the Buttondown dashboard.
This subscriber joined via Zapier.