Design per-mailbox e-mail billing and add-on gating

Shipped

August 26, 2026 at 7:45 PM UTC

Author

Kamo

Commit

dbe3f16

Bills e-mail by the mailbox rather than the seat, gates provider choice on the add-on that covers it, and attributes each mailbox to the billing group that should pay for it. Also covers two adjacent gaps the work runs into: is_primary is unique per member only, so a second member claiming a mailbox stops that address authenticating anyone; and the personal-mailbox provider path has a complete frontend contract with no backend behind it.