Twilio sends SMS one-time codes for this environment. Exactly one SMS provider is active at a time. With none active, SMS enrollment and SMS challenges are unavailable. Authenticator-app MFA does not need Twilio.

## Connect Twilio

In the [Authdog console](https://console.authdog.com):

1. Select the project and environment.
2. Open **Notifications**, then the **SMS** providers tab.
3. Choose **Twilio** and select **Connect**.
4. Fill in:

| Field | Value |
| --- | --- |
| **Account SID** | Starts with `AC`. From the [Twilio console](https://console.twilio.com) |
| **Auth token** | The account auth token. Stored encrypted. Leave blank later to keep the stored value |
| **Messaging Service SID** | Optional. Starts with `MG`. Use this or a from number |
| **From number** | Optional. E.164, for example `+15551234567`. Required if you do not set a Messaging Service |

5. Save. A newly connected provider becomes active.
6. Select **Test** and confirm the message arrives.

Provide a Messaging Service SID or a from number. Sending fails if both are missing.

## Use it for MFA

SMS MFA is a second factor, not a replacement for the primary sign-in.

1. Open **Authentication** and enable **Multi-factor authentication** for the environment.
2. Enroll a test user with SMS before you enforce it for everyone.
3. Sign in and confirm the six-digit code arrives from the number or messaging service you configured.

Connect a test Twilio account to development and the live account to production. Providers do not copy between environments.

## Related

| Read | To learn how to |
| --- | --- |
| [Multi-factor authentication](/docs/mfa) | Enrollment, reset, and which factors count |
| [Notifications](/docs/console/notifications) | Providers versus alert channels |
| [Marketplace](/marketplace/twilio) | The listing for this integration |