NewsletterSubscriptionStatus

NewsletterSubscriptionStatus = "subscribed" | "unsubscribed" | "unknown" | "pending" | string & object

Where a user stands on one newsletter list.

• subscribed and unsubscribed: set through this API.
• pending: double opt-in, waiting for the user to confirm by email.
• unknown: the user has never subscribed or unsubscribed. GET /subscriptions returns every list on the site, so one call can fill a preference centre without a second call to /lists.

Changes made in your email delivery platform are not read back. The union is open: show a status this client does not list as unknown.