The SMS step sends one text message to the contact's phone number. It uses **your own Twilio account**: Twilio bills you directly and Lumail adds no SMS cost.

## Connect Twilio

1. Open **Settings > Integrations > SMS (Twilio)**.
2. Paste your **Account SID** and **Auth Token** from the Twilio console. Lumail checks them with Twilio, then stores the token encrypted. It is never shown again.
3. Set a **Sender**: a Twilio number (`+33644600000`), an alphanumeric sender id (`LUMAIL`, where the country allows it) or a **Messaging Service SID**.
4. Set the **Default country** used to read local numbers such as `06 12 34 56 78`.
5. Copy the **STOP replies** URL into Twilio as the "A message comes in" webhook of your number or Messaging Service.
6. Send a test SMS to check the setup.

## Write the message

Merge tags work like in emails:

- `{{firstName}}`, `{{name}}`, `{{email}}`, `{{phone}}`
- custom fields by name, for example `{{city}}`
- a fallback after a pipe: `{{firstName | there}}`

The editor counts characters and SMS segments. One SMS holds 160 plain characters; an emoji or a special character drops it to 70.

## Who receives it

The step sends to contacts whose phone is valid. It skips, and the workflow continues, when:

- the contact has no phone or the number is not valid;
- the contact replied STOP (opt-out, shown on the contact timeline);
- the contact is unsubscribed or not active;
- no Twilio account is connected.

Each skip is written on the run timeline. A run that is retried never sends the same SMS twice, and test runs record the SMS without sending it.

## Webinar reminders

Combine SMS steps with [Event waits](/docs/workflows/workflow-wait-step): 1 day before, the morning of, 30 minutes before. A subscriber who arrives after a reminder's date skips it, SMS included.

## Related Documentation

- [Wait Step](/docs/workflows/workflow-wait-step)
- [Webhook Step](/docs/workflows/workflow-webhook-step)