SNS notification email/SMS body customization

Hi. If you are talking about the SNS rule action for the AWS IoT Core Rules engine then no. However you can introduce a Lambda to achieve it. Tutorial here: https://docs.aws.amazon.com/iot/latest/developerguide/iot-lambda-rule.html

If you require more sophisticated alert logic, you may consider using AWS IoT Events and this also supports customizing the notification messages using Lambda: https://docs.aws.amazon.com/iotevents/latest/developerguide/lambda-support.html. Alternatively, if you would visualize the data in Amazon Managed Grafana already, its alerts allow you to customize the message body: https://docs.aws.amazon.com/grafana/latest/userguide/alert-notifications.html#list-of-supported-notifiers