Verify Marketing API connectivity for the authenticated account (health check).
List audiences (lists) in the account with optional pagination.
Get a single audience (list) by ID.
List members of an audience with optional status filter and pagination.
Get a list member by email address (subscriber hash is derived automatically).
Add or update a list member (PUT). Creates if new, updates if hash exists.
Archive a list member (soft unsubscribe from the list).
List campaigns with optional status filter and pagination.