---
title: "Enable SMS on a number"
method: POST
path: "/v1/phone-numbers/{id}/sms"
tags: ["SMS"]
---

# Enable SMS on a number

`POST /v1/phone-numbers/{id}/sms`

Turns on SMS for one of your numbers. The number's real carrier
capability is checked first: some number types can't do SMS at all
(`smsCapable: false`), and a number still provisioning at the carrier
returns `notReady: true` (try again once provisioning finishes).

US numbers additionally need a carrier registration before messages
deliver; the response tells you which path applies:
- `alreadyRegistered: true`: a prior registration still covers this
  number; SMS was simply reactivated.
- `reusable` set: you have an approved registration this number can
  join in one click via
  `POST /v1/phone-numbers/{id}/sms/reuse-registration`
  (no new brand/campaign, no extra carrier fee).
- `needsRegistration: true` and no `reusable`: start one via
  `POST /v1/sms/registrations`.

Idempotent: re-running re-attempts any carrier-side setup that failed.

## Path parameters

- `id` string, required

## Response `200`

Result. Check `enabled`: a 200 with `enabled: false` means the number can't do SMS (`smsCapable: false`) or isn't ready yet (`notReady: true`).

- object
  - `enabled` boolean
  - `id` string — The SMS social account ID (present when enabled).
  - `phoneNumber` string
  - `isActive` boolean — False for US numbers until their registration is approved.
  - `country` string
  - `smsCapable` boolean, nullable — Null when capability can't be read yet (still provisioning).
  - `mmsCapable` boolean
  - `domesticOnly` boolean
  - `notReady` boolean — Number is still provisioning at the carrier; retry shortly.
  - `needsRegistration` boolean — US only; a carrier registration is required before delivery.
  - `alreadyRegistered` boolean — A prior non-rejected registration already covers this number; no re-submit needed.
  - `registrationStatus` 'pending' | 'approved' | 'rejected' | 'null', nullable
  - `reusable` object, nullable — Present when an existing approved registration can cover this number via /sms/reuse-registration.
    - `registrationId` string
    - `status` string
  - `message` string — Human-readable explanation when `enabled` is false.

## Other responses

- `401` — Unauthorized
- `404` — Number not found
- `422` — This number is hosted by your own carrier (brought via WhatsApp embedded signup), so SMS can't be enabled on it.

---

[API](https://skmtc.net/zernio/apis/zernio-api.md) · [All operations](https://skmtc.net/zernio/apis/zernio-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/zernio/zernio-api/versions/51932b099b2f/schema)