Design for New Solutions

StackSets deploy a stack across multiple accounts and Regions from a single template/admin account; nested stacks compose reusable child stacks within one stack in one account/Region.

It previews the exact resource additions, modifications, and replacements/deletions a stack update would cause before you execute it, reducing risk of unintended changes.

Resources whose actual configuration has diverged from the stack template (e.g., manual console edits), so you can reconcile out-of-band changes.

When you need to provision or configure something CloudFormation doesn't natively support, by invoking a Lambda function (or SNS) during create/update/delete lifecycle events.

CDK lets you define infrastructure in general-purpose languages and synthesizes it into CloudFormation templates that CloudFormation then deploys; CDK adds higher-level constructs and loops/abstractions.