https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/using-sam-cli.html now supports https://runfinch.com/ as an alternative to Docker for local development and testing of serverless applications. This gives developers greater flexibility in choosing their preferred local development environment when working with SAM CLI to build and test their serverless applications. Developers building serverless applications spend significant time in their local development environments. SAM CLI is a command-line tool for local development and testing of serverless applications. It allows you to build, test, debug, and package your serverless applications locally before deploying to AWS Cloud. To provide the local development and testing environment for your applications, SAM CLI uses a tool that can run containers on your local device. Previously, SAM CLI only supported Docker as the tool for running containers locally. Starting today, SAM CLI also supports Finch as a container development tool. Finch is an open-source tool, developed and supported by AWS, for local container development. This means you can now choose between Docker and Finch as your preferred container tool for local development when working with SAM CLI. You can use SAM CLI to invoke Lambda functions locally, test API endpoints, and debug your serverless applications with the same experience you would have in the AWS Cloud. With Finch support, SAM CLI now automatically detects and uses Finch as the container development tool when Docker is not available. You can also set Finch as your preferred container tool for SAM CLI. This new feature supports all core SAM CLI commands including sam build, sam local invoke, sam local start-api, and sam local start-lambda. To learn more about using SAM CLI with Finch, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/install-finch.html. 

AWS Serverless Application Model Command Line Interface (SAM CLI) now supports Finch as an alternative to Docker for local development and testing of serverless applications. This gives developers greater flexibility in choosing their preferred local development environment when working with SAM CLI to build and test their serverless applications. Developers building serverless applications spend significant time in their local development environments. SAM CLI is a command-line tool for local development and testing of serverless applications. It allows you to build, test, debug, and package your serverless applications locally before deploying to AWS Cloud. To provide the local development and testing environment for your applications, SAM CLI uses a tool that can run containers on your local device. Previously, SAM CLI only supported Docker as the tool for running containers locally. Starting today, SAM CLI also supports Finch as a container development tool. Finch is an open-source tool, developed and supported by AWS, for local container development. This means you can now choose between Docker and Finch as your preferred container tool for local development when working with SAM CLI. You can use SAM CLI to invoke Lambda functions locally, test API endpoints, and debug your serverless applications with the same experience you would have in the AWS Cloud. With Finch support, SAM CLI now automatically detects and uses Finch as the container development tool when Docker is not available. You can also set Finch as your preferred container tool for SAM CLI. This new feature supports all core SAM CLI commands including sam build, sam local invoke, sam local start-api, and sam local start-lambda. To learn more about using SAM CLI with Finch, visit the SAM CLI developer guide.

AWS Serverless Application Model (AWS SAM) now supports custom domain names for private REST APIs feature of Amazon API Gateway. Developers building serverless applications using SAM can now seamlessly incorporate custom domain names for private APIs directly in their SAM templates, eliminating the need to configure custom domain names separately using other tools. API Gateway allows you to create a custom domain name, like private.example.com, for your private REST APIs, enabling you to provide API callers with a simpler and intuitive URL. With a private custom domain name, you can reduce complexity, configure security measures with TLS encryption, and manage the lifecycle of the TLS certificate associated with your domain name. AWS SAM is a collection of open-source tools (e.g. SAM, SAM CLI) that make it easy for you to build and manage serverless applications through the authoring, building, deploying, testing, and monitoring phases of your development lifecycle. This launch enables you to easily configure custom domain names for your private REST APIs using SAM and SAM CLI. To get started, update SAM CLI to the latest version and modify your SAM template to set the EndpointConfiguration to PRIVATE and specify a policy document in the Policy field in the Domain property of the AWS::Serverless::Api resource. SAM will then automatically generate DomainNameV2 and BasePathMappingV2 resources under AWS::Serverless::Api. To learn more, visit the AWS SAM documentation. You can learn more about custom domain name for private REST APIs in API Gateway blog post.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/what-is-sam.html now supports WebSocket APIs for Amazon API Gateway, enabling you to define complete WebSocket APIs with minimal configuration in your SAM template. AWS SAM is a collection of open-source tools that make it easy for you to build and manage serverless applications. WebSocket APIs are critical for real-time applications such as chat, live dashboards, AI/LLM streaming, and IoT. However, SAM previously did not support WebSocket APIs, requiring you to manually configure all of the underlying resources in AWS CloudFormation. This made it difficult to debug common issues such as missing IAM permissions for Lambda functions. Now, SAM handles all of this automatically, generating the required resources and permissions from your template. The new resource provides feature parity with https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-websocket-api-overview.html, including IAM and Lambda authorization, custom domains, RouteSettings, Models, and StageVariables. Globals support lets you share common configuration across multiple WebSocket APIs. To get started, add the AWS::Serverless::WebSocketApi resource type to your SAM template. Define your routes by specifying Lambda function handlers for $connect, $disconnect, and $default routes, along with any custom routes your application requires. SAM automatically wires up the integrations and permissions for each route. You can also configure authorization, stage settings, and custom domains directly within the resource definition. To learn more, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-websocketapi.html.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/using-sam-cli.html now supports BuildKit for building container images from Dockerfiles, enabling faster, more efficient container image builds for Lambda functions packaged as container images. SAM CLI is a command-line tool for building, testing, debugging, and packaging serverless applications locally before deploying to AWS Cloud. Developers packaging Lambda functions as container images often need advanced build features provided by BuildKit to optimize their images for production. However, SAM CLI previously did not support BuildKit features. Now, with BuildKit support in SAM CLI, you can utilize multi-stage builds to create smaller final images without development dependencies, improved caching to reduce rebuild times, and better parallelization of build steps. BuildKit also enables cross-architecture builds, allowing you to build container images targeting both x86_64 and arm64 (AWS Graviton2) instruction set architectures from the same development machine. You can also use Docker secrets during builds, keeping sensitive data such as credentials and API keys out of your final image layers. To get started, download or update SAM CLI to version 1.159.0 or later and use the --use-buildkit flag with sam build. This feature works regardless of whether you are using Docker or Finch with SAM CLI, unlocking the full set of BuildKit capabilities. To learn more, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-cli-command-reference-sam-build.html.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/using-sam-cli.html now supports https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/transform-aws-languageextensions.html, enabling you to reduce duplication in your infrastructure as code (IaC) templates while retaining the full local development workflow. This accelerates your serverless development by letting you define resources once and iterate locally without waiting for cloud deployments. Developers frequently need to define multiple similar resources, such as Lambda functions, DynamoDB tables, or SNS topics, from a single template definition. However, developers who use SAM CLI to build, test, and deploy their serverless applications previously could not process templates that use CloudFormation Language Extensions. This required choosing between reducing template duplication and using SAM CLI for local development. Now, SAM CLI processes Language Extensions in memory for local operations while preserving your original template for CloudFormation deployment. You can define your resources once and test them locally across all SAM CLI commands, catching errors like invalid syntax or missing dependencies before deploying. This shortens your iteration cycles and reduces time spent debugging failed deployments in the cloud. To get started, download or update SAM CLI to the latest version. Add the AWS::LanguageExtensions transform to your SAM template and use Fn::ForEach to generate multiple resources from a single definition. SAM CLI commands including sam build, sam local invoke, sam sync, sam local start-api, and sam validate will automatically expand your loops and process each generated resource. You can invoke expanded functions by name, for example sam local invoke AlphaFunction. SAM CLI also supports Fn::Length, Fn::ToJsonString, Fn::FindInMap with DefaultValue, and conditional DeletionPolicy and UpdateReplacePolicy attributes. To learn more, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-specification-language-extensions.html and https://builder.aws.com/content/3DiJq5vQ2hnGq1ddBlCApT8uy6u/dynamic-looping-comes-to-aws-sam.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/what-is-sam.html now supports WebSocket APIs for Amazon API Gateway, enabling you to define complete WebSocket APIs with minimal configuration in your SAM template. AWS SAM is a collection of open-source tools that make it easy for you to build and manage serverless applications. WebSocket APIs are critical for real-time applications such as chat, live dashboards, AI/LLM streaming, and IoT. However, SAM previously did not support WebSocket APIs, requiring you to manually configure all of the underlying resources in AWS CloudFormation. This made it difficult to debug common issues such as missing IAM permissions for Lambda functions. Now, SAM handles all of this automatically, generating the required resources and permissions from your template. The new resource provides feature parity with https://docs.aws.amazon.com/apigateway/latest/developerguide/apigateway-websocket-api-overview.html, including IAM and Lambda authorization, custom domains, RouteSettings, Models, and StageVariables. Globals support lets you share common configuration across multiple WebSocket APIs. To get started, add the AWS::Serverless::WebSocketApi resource type to your SAM template. Define your routes by specifying Lambda function handlers for $connect, $disconnect, and $default routes, along with any custom routes your application requires. SAM automatically wires up the integrations and permissions for each route. You can also configure authorization, stage settings, and custom domains directly within the resource definition. To learn more, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-websocketapi.html.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/using-sam-cli.html now supports BuildKit for building container images from Dockerfiles, enabling faster, more efficient container image builds for Lambda functions packaged as container images. SAM CLI is a command-line tool for building, testing, debugging, and packaging serverless applications locally before deploying to AWS Cloud. Developers packaging Lambda functions as container images often need advanced build features provided by BuildKit to optimize their images for production. However, SAM CLI previously did not support BuildKit features. Now, with BuildKit support in SAM CLI, you can utilize multi-stage builds to create smaller final images without development dependencies, improved caching to reduce rebuild times, and better parallelization of build steps. BuildKit also enables cross-architecture builds, allowing you to build container images targeting both x86_64 and arm64 (AWS Graviton2) instruction set architectures from the same development machine. You can also use Docker secrets during builds, keeping sensitive data such as credentials and API keys out of your final image layers. To get started, download or update SAM CLI to version 1.159.0 or later and use the --use-buildkit flag with sam build. This feature works regardless of whether you are using Docker or Finch with SAM CLI, unlocking the full set of BuildKit capabilities. To learn more, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-cli-command-reference-sam-build.html.

https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/what-is-sam.html (AWS SAM) now supports custom domain names for private REST APIs feature of https://docs.aws.amazon.com/apigateway/latest/developerguide/welcome.html. Developers building serverless applications using SAM can now seamlessly incorporate custom domain names for private APIs directly in their SAM templates, eliminating the need to configure custom domain names separately using other tools. API Gateway allows you to create a custom domain name, like private.example.com, for your private REST APIs, enabling you to provide API callers with a simpler and intuitive URL. With a private custom domain name, you can reduce complexity, configure security measures with TLS encryption, and manage the lifecycle of the TLS certificate associated with your domain name. AWS SAM is a collection of open-source tools (e.g. SAM, SAM CLI) that make it easy for you to build and manage serverless applications through the authoring, building, deploying, testing, and monitoring phases of your development lifecycle. This launch enables you to easily configure custom domain names for your private REST APIs using SAM andhttps://docs.aws.amazon.com/serverless-application-model/latest/developerguide/using-sam-cli.html. To get started, update SAM CLI to the latest version and modify your SAM template to set the EndpointConfiguration to PRIVATE and specify a policy document in the Policy field in the Domain property of the AWS::Serverless::Api resource. SAM will then automatically generate DomainNameV2 and BasePathMappingV2 resources under AWS::Serverless::Api. To learn more, visit the https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-api.html. You can learn more about custom domain name for private REST APIs in https://aws.amazon.com/blogs/compute/implementing-custom-domain-names-for-private-endpoints-with-amazon-api-gateway/.  

AWS SAM CLI now supports AWS CloudFormation Language Extensions, enabling you to reduce duplication in your infrastructure as code (IaC) templates while retaining the full local development workflow. This accelerates your serverless development by letting you define resources once and iterate locally without waiting for cloud deployments. Developers frequently need to define multiple similar resources, such as Lambda functions, DynamoDB tables, or SNS topics, from a single template definition. However, developers who use SAM CLI to build, test, and deploy their serverless applications previously could not process templates that use CloudFormation Language Extensions. This required choosing between reducing template duplication and using SAM CLI for local development. Now, SAM CLI processes Language Extensions in memory for local operations while preserving your original template for CloudFormation deployment. You can define your resources once and test them locally across all SAM CLI commands, catching errors like invalid syntax or missing dependencies before deploying. This shortens your iteration cycles and reduces time spent debugging failed deployments in the cloud. To get started, download or update SAM CLI to the latest version. Add the AWS::LanguageExtensions transform to your SAM template and use Fn::ForEach to generate multiple resources from a single definition. SAM CLI commands including sam build, sam local invoke, sam sync, sam local start-api, and sam validate will automatically expand your loops and process each generated resource. You can invoke expanded functions by name, for example sam local invoke AlphaFunction. SAM CLI also supports Fn::Length, Fn::ToJsonString, Fn::FindInMap with DefaultValue, and conditional DeletionPolicy and UpdateReplacePolicy attributes. To learn more, visit the SAM CLI developer guide and launch blog post.

AWS Serverless Application Model (AWS SAM) now supports WebSocket APIs for Amazon API Gateway, enabling you to define complete WebSocket APIs with minimal configuration in your SAM template. AWS SAM is a collection of open-source tools that make it easy for you to build and manage serverless applications. WebSocket APIs are critical for real-time applications such as chat, live dashboards, AI/LLM streaming, and IoT. However, SAM previously did not support WebSocket APIs, requiring you to manually configure all of the underlying resources in AWS CloudFormation. This made it difficult to debug common issues such as missing IAM permissions for Lambda functions. Now, SAM handles all of this automatically, generating the required resources and permissions from your template. The new resource provides feature parity with API Gateway WebSocket APIs, including IAM and Lambda authorization, custom domains, RouteSettings, Models, and StageVariables. Globals support lets you share common configuration across multiple WebSocket APIs. To get started, add the AWS::Serverless::WebSocketApi resource type to your SAM template. Define your routes by specifying Lambda function handlers for $connect, $disconnect, and $default routes, along with any custom routes your application requires. SAM automatically wires up the integrations and permissions for each route. You can also configure authorization, stage settings, and custom domains directly within the resource definition. To learn more, visit the SAM developer guide.

AWS Serverless Application Model Command Line Interface (SAM CLI) now supports BuildKit for building container images from Dockerfiles, enabling faster, more efficient container image builds for Lambda functions packaged as container images. SAM CLI is a command-line tool for building, testing, debugging, and packaging serverless applications locally before deploying to AWS Cloud. Developers packaging Lambda functions as container images often need advanced build features provided by BuildKit to optimize their images for production. However, SAM CLI previously did not support BuildKit features. Now, with BuildKit support in SAM CLI, you can utilize multi-stage builds to create smaller final images without development dependencies, improved caching to reduce rebuild times, and better parallelization of build steps. BuildKit also enables cross-architecture builds, allowing you to build container images targeting both x86_64 and arm64 (AWS Graviton2) instruction set architectures from the same development machine. You can also use Docker secrets during builds, keeping sensitive data such as credentials and API keys out of your final image layers. To get started, download or update SAM CLI to version 1.159.0 or later and use the --use-buildkit flag with sam build. This feature works regardless of whether you are using Docker or Finch with SAM CLI, unlocking the full set of BuildKit capabilities. To learn more, visit the SAM CLI developer guide.