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

# Outbound SMS

> Send text messages from a workspace phone number — requirements, segment billing, and the send endpoint

Send outbound SMS from a phone number that belongs to your workspace and has **Allow outbound SMS** enabled.

## Who can send SMS

| Number source                                                    | Requirements                                                                                     | Billing                                                                 |
| ---------------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------- |
| [Marketplace](/telephony/phone-numbers) (bought on the platform) | `sms_capable` + outbound SMS enabled                                                             | Platform SMS credits **including** carrier pass-through                 |
| [Twilio import (BYOC)](/telephony/carrier-import)                | Twilio carrier connection, `sms_capable`, outbound SMS enabled, A2P registered for US 10DLC → US | Platform SMS credits only (you pay Twilio carrier cost on your account) |

## How message length affects cost

SMS is billed per **segment**, not per message. One segment holds:

* **160 characters** of plain ASCII text, or
* **70 characters** if the message contains anything outside that set — emoji, most accented letters, or a small set of symbols like `{ } [ ] ~ ^ | €`.

A message longer than one segment's worth of characters is automatically split into multiple segments, each billed at the same per-segment rate shown in the table above. Keeping messages in plain ASCII and under 160 characters is the cheapest and most predictable option.

## Enable outbound SMS

1. Open **Settings → Numbers** and select the number.
2. Open the **SMS** tab (visible when the number is SMS-capable).
3. Enable **Allow outbound SMS**.
4. For US 10DLC numbers, complete A2P 10DLC registration in your Twilio account and wait until the number is linked to an approved campaign.

## REST API

```bash theme={null}
curl -X POST "https://{domain}/api/v1/sms/send" \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from_number_id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
    "to": "+14155550100",
    "body": "Hello from the platform"
  }'
```

**Required scope:** `phone_numbers:write`

See also: OpenAPI `POST /sms/send`, MCP tool `send_sms`.