AWS has added CloudFormation Language Extensions support to the AWS SAM CLI, closing a gap between cleaner infrastructure templates and local serverless development.
The practical change is that SAM CLI can now process templates using the AWS::LanguageExtensions transform. That matters for teams using features such as Fn::ForEach to define repeated infrastructure from a single template pattern rather than copying and editing near-identical blocks.
AWS gives the familiar examples: multiple Lambda functions, DynamoDB tables or SNS topics that share a structure but differ in names, properties or configuration. Previously, developers using SAM CLI to build, test and deploy serverless applications could hit problems if their templates used CloudFormation Language Extensions. That created an annoying split: keep the templates DRY, or preserve the full local SAM workflow.
The update means SAM commands including sam build, sam local invoke, sam sync and sam local start-api can work with these extended templates. AWS’s setup guidance is straightforward: update SAM CLI, add the AWS::LanguageExtensions transform to the SAM template, and use Fn::ForEach to generate resources from a single definition.
For a platform team, this is not headline-grabbing infrastructure news. It removes friction from the boring part of serverless work: keeping templates maintainable while still allowing developers to iterate locally.
That is especially relevant in agency or product environments where a team maintains standard infrastructure modules across several client projects. Repetition in CloudFormation templates is not just untidy; it creates drift. One resource gets the updated alarm, timeout, tag or policy, and another copy quietly does not. Language extensions help reduce that copy-paste surface, but only if local tooling can keep up.