Configuring verification and invitation messages

With Amazon Cognito, you can customize SMS and email verification messages and user invitation messages, to enhance the security and user experience of your application. With Amazon Cognito, you can choose between code-based or one-click link verifications to suit your application's needs. This topic discusses how you can personalize multi-factor authentication (MFA) and verification communications in the Amazon Cognito console.

In the Messaging tab under Message templates, you can customize:

Message templates

You can use message templates to insert placeholders into your messages. Amazon Cognito replace the placeholders with the corresponding values. You can reference Universal template placeholders in message templates of any type, although these values won't be present in all message types.

One of the available automated responses with advanced security features is to notify the user that Amazon Cognito detected potentially-malicious activity. You can use advanced security template placeholders to do the following:

Advanced security features add the following placeholders that you can insert into message templates:

Customizing the SMS message

You can customize the SMS message for multi-factor authentication (MFA) in the Messaging tab under the Message templates heading.

Amazon Cognito imposes a maximum length for SMS messages, including the authentication code, at 140 UTF-8 characters.

Customizing SMS verification messages

You can customize the SMS message for phone number verifications by editing the template under the Do you want to customize your SMS verification messages? heading.

The maximum length for the message, including the verification code, is 140 UTF-8 characters.

Customizing email verification messages

To verify the email address of a user in your user pool with Amazon Cognito, you can send the user an email message with a link that they can select, or you can send them a code that they can enter.

To customize the email subject and message content for email address verification messages, edit the Verification message template in the Messaging tab of your user pool. You can choose a Verification type of Code or Link when you edit your Verification message template.

When you choose Code as the verification type, your custom message must contain the {####} placeholder. When you send the message, the verification code replaces this placeholder.

When you choose Link as the verification type, your custom message must include a placeholder in the format {##Verify Your Email##}. You can change the text string between the placeholder characters, for example {##Click here##}. A verification link titled Verify Your Email replaces this placeholder.

The link for an email verification message directs your user to a URL like the following example.

https://<your user pool domain>/confirmUser/?client_id=abcdefg12345678&user_name=emailtest&confirmation_code=123456

The maximum length for the message, including the verification code (if present), is 20,000 UTF-8 characters. You can use HTML tags in this message to format the contents.

Customizing user invitation messages

You can customize the user invitation message that Amazon Cognito sends to new users by SMS or email message by editing the Invitation messages template in the Messaging tab.

The maximum length of an SMS message, including the verification code, is 140 UTF-8 characters. The maximum length of an email message, including the verification code, is 20,000 UTF-8 characters. You may use HTML tags in your email messages to format the contents.

Customizing your email address

By default, Amazon Cognito sends email messages to users in your user pools from the address no-reply@verificationemail.com. You can choose to specify custom FROM and REPLY-TO email addresses instead of no-reply@verificationemail.com.

Authorizing Amazon Cognito to send Amazon SES email on your behalf (from a custom FROM email address)

You can configure Amazon Cognito to send email from a custom FROM email address instead of its default address. To use a custom address, you must give Amazon Cognito permission to send email message from an Amazon SES verified identity. In most cases, you can grant permission by creating a sending authorization policy. For more information, see Using sending authorization with Amazon SES in the Amazon Simple Email Service Developer Guide.

When you configure a user pool to use Amazon SES for email messages, Amazon Cognito creates the AWSServiceRoleForAmazonCognitoIdpEmailService role in your account to grant access to Amazon SES. No sending authorization policy is needed when the AWSServiceRoleForAmazonCognitoIdpEmailService service-linked role is used. You only need to add a sending authorization policy when you use both the default email functionality in your user pool and a verified Amazon SES identity as the FROM address.

For more information about the service-linked role that Amazon Cognito creates, see Using service-linked roles for Amazon Cognito.

The following example sending authorization policy grants Amazon Cognito a limited ability to use an Amazon SES verified identity. Amazon Cognito can only send email messages when it does so on behalf of both the user pool in the aws:SourceArn condition and the account in the aws:SourceAccount condition. For more examples, see Amazon SES sending authorization policy examples in the Amazon Simple Email Service Developer Guide.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "stmnt1234567891234",
            "Effect": "Allow",
            "Principal": {
                "Service": [
                    "email.cognito-idp.amazonaws.com"
                ]
            },
            "Action": [
                "SES:SendEmail",
                "SES:SendRawEmail"
            ],
            "Resource": "<your SES identity ARN>",
            "Condition": {
                "StringEquals": {
                    "aws:SourceAccount": "<your account number>"
                },
                "ArnLike": {
                    "aws:SourceArn": "<your user pool ARN>"
                }
            }
        }
    ]
}

The Amazon Cognito console adds a similar policy for you when you select an Amazon SES identity from the drop-down menu. If you use the CLI or API to configure the user pool, you must attach a policy structured like the previous example to your Amazon SES Identity.