ECS and EKS are powerful but operationally complex. Task Definition, Service, ALB Target Group, Security Group, IAM Role—running one ECS service properly requires managing dozens of AWS resources. Does a startup or small team need all this for a single web API?
App Runner answers "no." "Give me source code or image; I handle the rest"—builds, deployment, load balancing, SSL, auto-scaling, monitoring—AWS completely manages. ECS Copilot is the middle ground: keep full ECS control while hiding complex resource configuration behind CLI abstraction.
Today we understand the abstraction spectrum and develop exam ability to immediately judge "which service for which situation?"