# Sender status

Source: https://joinsimplesms.com/changelog/2026-10-04-sender-status
Index: https://joinsimplesms.com/llms.txt

October 4, 2026

- **Numbers show where they stand.** Every number carries `sender`
  (`test_only`, `pending`, `active`, `action_needed` with a plain
  reason). New `GET /v1/numbers/{number}`, and the
  `number.sender_updated` event. See [Numbers](/docs/numbers#sender-status).
- **Test only until registered.** A live US number that is not linked to an
  approved registration can text your verified numbers and nobody else. Other
  sends answer `403 sender_not_registered` with
  `X-Delivered-Sender-State`. This replaces the
  `X-Delivered-Registration` / `X-Delivered-Warning` headers, which are
  gone: unregistered traffic is now stopped instead of warned about.
- **Automatic linking.** When a registration is approved, the account's live
  numbers are linked to it and become `active`; numbers bought later link
  on their own. `POST /v1/numbers/{number}/registration` chooses a
  registration explicitly (up to 49 numbers each).
- **One form to go live.** Submitting a registration from a sandbox account
  is also the live-access request. Submit now requires complete business
  details and answers `400` naming what is missing.