What service would be used for automated application scaling in AWS?

Automated application scaling in AWS is primarily achieved through Amazon EC2 Auto Scaling. This service enables you to automatically adjust the number of EC2 instances in response to the current demand for applications hosted on those instances. By using predefined scaling policies, it ensures that you have the right amount of compute resources at any given time, which helps maintain performance and minimize costs.

EC2 Auto Scaling monitors the performance and health of your applications, allowing for dynamic adjustments to scale out (by adding instances during high demand) or scale in (by removing instances during lower demand). This capability is crucial for applications that experience variable loads, as it optimizes resource usage and enhances end-user experience by ensuring that applications remain responsive and available.

The other services listed do not focus on automated scaling. AWS CloudFormation is a tool used for provisioning AWS resources in a predictable and repeatable way using templates. AWS Config is a service that provides a detailed view of the configuration of AWS resources in your account, useful for compliance and auditing. Amazon Route 53 is a scalable Domain Name System (DNS) web service that translates human-friendly domain names into IP addresses but does not manage application scaling.