The shape of the work decides between serverless and containers. AWS Lambda runs code in response to events or web requests without servers to manage, scales with traffic and bills for use, which suits APIs, background jobs and uneven demand.
Containers on Amazon ECS with Fargate suit long-running services, steady traffic and applications that already ship as containers. Static front ends are served through a content delivery network, and data lives in managed databases with automatic backups.
The architecture plan gives the reason for each choice. A growing product can use both, as in multi-tenant software platforms, where one part responds to events and another runs as a long-lived service.








