> ## Documentation Index
> Fetch the complete documentation index at: https://docs.telzino.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Add an SMS Number

> Assign a hosted SMS number to an organization

A number belongs to one organization, which receives its texts and can send from it. This call needs a partner-level API key.

> [!WARNING]
>
> Adding a number only records it. Before texts work, the number must be routed to the Telzino SMS webhook and the Telzino API key must be allowed on it at the carrier. If the API key is not allowed, texts arrive but every reply fails. Your Telzino contact has the details.

The organization also needs the **Hosted SMS** feature to send during calls, or **SMS & Email Conversations** for its agents to answer texts. Adding a number does not unlock either one. See [Feature Administration](https://docs.telzino.com/admin-guide/dashboard/feature-administration.md).

## Path Parameters

**organization\_id** `string` *required*

The organization's UUID

## Body

**phone\_number** `string` *required*

The number in E.164 format, for example `+13234137301`. Any other format is refused.

```bash cURL theme={null}
curl -X POST "https://api.telzino.com/v1/organizations/234cd323-…/sms-numbers" \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{ "phone_number": "+13234137301" }'
```

```json 201 theme={null}
{
  "data": {
    "phone_number": "+13234137301",
    "organization_id": "234cd323-…",
    "created_at": "2026-11-05T00:00:00.000Z"
  }
}
```

| Code | Meaning |
| - | - |
| `201` | Added |
| `200` | The organization already has this number. Nothing changed, so a retry is safe. |
| `400` | The number is not valid E.164, or the body is not JSON |
| `403` | The API key is not partner-level |
| `404` | Organization not found |
| `409` | The number is not available (`number_unavailable`) |


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