Vonage sends SMS one-time codes for this environment. A newly connected SMS provider becomes the one that sends. Other connected SMS providers stay as fallbacks after a hard failure. With none connected, SMS sign-in and SMS MFA cannot send a code. Authenticator-app MFA does not need Vonage.

## Connect Vonage

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

1. Select the project and environment.
2. Open **Notifications > Providers**.
3. Select the **SMS** channel.
4. Choose **Vonage** and select **Connect**.
5. Enter:

| Field | Value |
| --- | --- |
| **API key** | From the Vonage account |
| **API secret** | Stored encrypted. Leave blank on a later edit to keep the stored secret |
| **From number / sender ID** | E.164 number, for example `+15551234567`, or an alphanumeric sender ID the account is allowed to use |

6. Save. Vonage becomes the active SMS provider.
7. Select **Test** and confirm the message arrives.

The sender must be one Vonage will accept for the destination country. An alphanumeric sender ID that works in one country is rejected in another.

## Use it for sign-in or MFA

SMS codes are a channel. Turn the method on separately.

1. For passwordless sign-in, open **Authentication > Methods** and enable **SMS**.
2. For a second factor, open **Authentication** and enable **Multi-factor authentication**, then enroll a test user with SMS before you enforce it.
3. Sign in and confirm the code arrives from the sender you configured.

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

## Related

| Read | To learn how to |
| --- | --- |
| [SMS code](/marketplace/sms-otp/setup) | Enable the passwordless SMS method |
| [Multi-factor authentication](/docs/mfa) | Enrollment, reset, and which factors count |
| [Marketplace](/marketplace/vonage) | The listing for this integration |