externalId

The external ID is a value. We recommend you use ExternalId to add security to your IAM role, which is used to call Amazon SNS to send SMS messages for your user pool. If you provide an ExternalId , the Cognito User Pool uses it when attempting to assume your IAM role. You can also set your roles trust policy to require the ExternalID . If you use the Cognito Management Console to create a role for SMS MFA, Cognito creates a role with the required permissions and a trust policy that uses ExternalId .