You can use AWS IoT with Amazon Cognito Identity. Devices connected to AWS IoT are represented by things in the registry. The registry allows you to keep a record of all of the devices that are connected to your AWS IoT account.
The fastest way to start using your AWS IoT Button is to download the mobile app for iOS or Android. The mobile app creates the required AWS IoT resources for you, and adds an event source to your button that uses a Lambda blueprint to invoke a new AWS Lambda function of your choice. Blueprints are preconfigured Lambda functions that allow you to quickly connect the click of a button to the functions that fit you best, such as sending automated emails or text messages or deploying other AWS services. You can download the mobile apps from The Apple App Store or Google Play.
https://docs.aws.amazon.com/iot/latest/developerguide/register-device.html
https://docs.aws.amazon.com/iot/latest/developerguide/cognito-identities.html