AWS Application Auto Scaling is a service that enables automatic adjustment of the size and number of AWS resources to match changing workloads. Unlike the classic Amazon EC2 Auto Scaling, it also supports other AWS services such as Amazon ECS (scaling tasks or container services), Amazon EMR (big data clusters), Amazon DynamoDB (tables and throughput), and Amazon AppStream 2.0.

It allows you to define scaling policies, for example, based on CloudWatch metrics, set minimum and maximum resource limits, and create rules that automatically start or stop instances in response to demand. This helps maintain high application availability and performance while reducing costs.

Application Auto Scaling is fully managed by AWS, which simplifies configuration and allows you to focus on application development instead of manually adjusting the infrastructure.