LocalStack

New Lambda Runtime Support

LocalStack for AWS 4.11 includes several Lambda runtime updates including:

• Python 3.14
• Java 25
• Node.js 24

You can learn more about deploying Lambdas to LocalStack in our documentation and more about Lambda supported runtimes in the AWS documentation.

Improved KMS Support

AWS Key Management Service (KMS allows you to easily create, control, and manage the cryptographic keys used to encrypt and protect your data across your applications and AWS resources. LocalStack for AWS 4.11 adds to our already extensive KMS coverage by adding support for a recipient in KMS decrypt and on-demand key rotation for external keys.

KMS Decrypt Recipient

LocalStack for AWS 4.11 now supports the KMS Decrypt Recipient field is used by AWS Nitro Enclaves to decrypt sensitive keys without the host being able to read them. You can read more about this flow in the KMS Decrypt documentation.

KMS On-demand Key Rotation

KMS: On Demand Key Rotation for Imported Key Material
Earlier this year, AWS made it possible to import custom key material into external keys thereby allowing use of KeyRotationOnDemand with external KMS keys. This capability is now also supported in LocalStack for AWS as of 4.11.

Expanded API Support for MSK, S3 Tables and CodePipeline

At LocalStack, we are always striving to expand our AWS API coverage to ensure our customers can accurately test their complete end-to-end workflow. LocalStack for AWS 4.11 continues this effort with expanded API support for a number of services.

MSK

Tagging resources in Amazon Managed Streaming for Apache Kafka (MSK) is a powerful and simple way to manage, organize, and control access to your resources. LocalStack for AWS 4.11 inclues support for tagging MSK Resources.

API operations that were added include:

• TagResource
• UntagResource
• ListTagsForResource

For details on using MSK within LocalStack as well as full API coverage details, visit our MSK documentation.

S3 Tables

Amazon S3 Tables provide support APIs that allow users to configure, monitor, and control the management and performance of individual tables. As of LocalStack for AWS 4.11, we support the following S3 Tables support APIs:

• GetTableBucketMaintenanceConfiguration
• PutTableBucketMaintenanceConfiguration
• GetTableMaintenanceConfiguration
• PutTableMaintenanceConfiguration

Note that the APIs accept, validate, store, and return maintenance configurations, but the actual maintenance operations (file removal, compaction, snapshot management) are not actively executed.

For more details on using S3 Tables in LocalStack, check our S3 Tables documentation.

CodePipeline

Our team at LocalStack regularly monitors API usage to help identify gaps in API coverage for actively requested APIs. One such missing operation recently identified by our team was the GetPipelineState operation in CodePipeline used to retrieve the state of a pipeline, including the stages and actions. LocalStack for AWS 4.11 resolves this API coverage gap.

For information about how to use CodePipeline within LocalStack, including full API coverage details, visit our CodePipeline documentation.

RDS Support for pgvector

LocalStack continues to improve upon its capabilities in building and testing artificial intelligence (AI) and machine learning (ML) applications. AWS previously announced support for the pgvector extension for Amazon Relational Database Service (RDS) for PostgreSQL. This extension is used to store embeddings from ML models in order to more efficiently perform similarity searches. With LocalStack for AWS 4.11, the pgvector extension is now installed by default when installing a version of Postgres allowing improved emulation of ML workloads.

Enhanced EKS Persistence

Persistence on LocalStack allows you to save and even share the state of your LocalStack instance. This can enable quick and easy setup of complex environments across sessions, between team members or in CI/CD. However, until LocalStack for AWS 4.11, EKS (Elastic Kubernetes Service) persistence was limited as it did not persist the contents of the cluster.

LocalStack for AWS 4.11 has added the ability to persist the state and contents of your emulated EKS clusters between restarts, enabling faster iteration and more realistic local testing of Kubernetes workloads.

By default, cluster contents are not persisted. You can enable saving/loading your Kubernetes resources by starting LocalStack with EKS_PERSIST_CLUSTER_CONTENTS=1. The persistence capability uses Velero under the hood, and we've also exposed EKS_VELERO_IMAGE and EKS_VELERO_PLUGIN_AWS_IMAGE to allow further customization of the Velero image and the AWS plugin image.

Miscellaneous

• Fixed an issue where the public IP address of EC2 instances started in K8S environment would not resolve to the instances pod.
• Fixed the Kafka cluster version in the MSK ListClusters and DescribeCluster APIs.
• Fixed an issue where the pod would not be removed when deleting the cluster or stopping LocalStack when running Redis/Valkey container in K8s environment.
• Fixed an issue reported that caused a GraphQL schema error in AppSync when defining AWSDateTime or AWSTimestamp scalars.

Deprecations

• Starting LocalStack in host mode via the CLI using localstack start --host has been deprecated and is expected to be removed in January 2026. Users of this features are advised to use the default Docker mode instead.

What's Changed

Exciting New Features 🎉

• Lambda: Support python3.14 and java25 runtimes by @dfangl in https://github.com/localstack/localstack/pull/13348
• Update deprecated type annotations produced by AWS scaffold tool by @purcell in https://github.com/localstack/localstack/pull/13347
• Sns:v2 platform endpoint operations by @baermat in https://github.com/localstack/localstack/pull/13327
• Add support for recipient for KMS Decrypt by @mboorstin-circle in https://github.com/localstack/localstack/pull/13343
• deprecate starting in host mode via the CLI by @alexrashed in https://github.com/localstack/localstack/pull/13398
• KMS: On Demand Key Rotation for Imported Key Material by @aidehn in https://github.com/localstack/localstack/pull/13363
• Step Functions: fix validate-state-machine-definition by @YukiMichishita in https://github.com/localstack/localstack/pull/13281
• refactor the global analytics bus to use a generic async batching util by @thrau in https://github.com/localstack/localstack/pull/13279
• Sns:v2 publish by @baermat in https://github.com/localstack/localstack/pull/13399

Other Changes

• K8s tests: Add requires_in_process marker in only_localstack tests where needed by @nik-localstack in https://github.com/localstack/localstack/pull/13303
• Add marker for skipping k8s tests by @nik-localstack in https://github.com/localstack/localstack/pull/13324
• IAM: refactor simulation into simulator class by @pinzon in https://github.com/localstack/localstack/pull/13326
• Change one of the test domains for the DNS tests by @dfangl in https://github.com/localstack/localstack/pull/13333
• Update localstack.dev.kubernetes script to expose DNS port by @nik-localstack in https://github.com/localstack/localstack/pull/13320
• Propose fix two typos by @jeis4wpi in https://github.com/localstack/localstack/pull/13341
• OpenSearch: Disable SSL validation for unsupported regions by @dfangl in https://github.com/localstack/localstack/pull/13346
• services/logs: Add ListLogGroups operation by @purcell in https://github.com/localstack/localstack/pull/13337
• IaC: Load the AWS catalog from the platform or cached file by @k-a-il in https://github.com/localstack/localstack/pull/13179
• UNC-99 apigateway accept-encoding header wrong by @cloutierMat in https://github.com/localstack/localstack/pull/13350
• Move steps for updating ASF modules to Makefile by @purcell in https://github.com/localstack/localstack/pull/13354
• Remove redundant ruff ignores for generated ASF modules by @purcell in https://github.com/localstack/localstack/pull/13355
• update kinesis-mock from 0.4.13 to 0.4.14 by @alexrashed in https://github.com/localstack/localstack/pull/13360
• Explicitly fix import order when regenerating ASF modules by @purcell in https://github.com/localstack/localstack/pull/13362
• Update Boto3 stubs by @viren-nadkarni in https://github.com/localstack/localstack/pull/13367
• Fix DNS port mapping in localstack.dev.kubernetes by @nik-localstack in https://github.com/localstack/localstack/pull/13361
• update kinesis-mock from 0.4.14 to 0.5.1 by @alexrashed in https://github.com/localstack/localstack/pull/13371
• S3: fix aws-global as location constraint by @bentsku in https://github.com/localstack/localstack/pull/13353
• CFn: raise validation error in get-template if no arguments by @simonrw in https://github.com/localstack/localstack/pull/13380
• Update README.md for 4.10 by @purcell in https://github.com/localstack/localstack/pull/13378
• Change error code from 500 to 501 in case plugin is not available in users license by @sannya-singal in https://github.com/localstack/localstack/pull/13344
• upgrade lambda-runtime-init by @carole-lavillonniere in https://github.com/localstack/localstack/pull/13385
• Update CODEOWNERS by @localstack-bot in https://github.com/localstack/localstack/pull/13383
• clean-up references to CircleCI by @bentsku in https://github.com/localstack/localstack/pull/13392
• APIGW: fix GetIntegration error messages by @bentsku in https://github.com/localstack/localstack/pull/13393
• APIGW: fix errors when importing invalid json/yaml by @bentsku in https://github.com/localstack/localstack/pull/13394
• SQS: fix FIFO message visiblity when extending timeout by @baermat in https://github.com/localstack/localstack/pull/13386
• S3: fix ListBuckets with invalid region name by @bentsku in https://github.com/localstack/localstack/pull/13396
• S3: fix CopyObject preconditions check to be with second-resolution by @bentsku in https://github.com/localstack/localstack/pull/13381
• CFn: raise validation error if the template is not valid by @simonrw in https://github.com/localstack/localstack/pull/13377
• update usage of deprecated utcnow() in service request aggregator by @dmacvicar in https://github.com/localstack/localstack/pull/13373
• fix deprecation warning for xml.ElementTree by @bentsku in https://github.com/localstack/localstack/pull/13405
• CFn: validate conditions exist in Fn::If by @simonrw in https://github.com/localstack/localstack/pull/13243
• kms: Fix ECDH derive-shared-secret behavior by @sannya-singal in https://github.com/localstack/localstack/pull/13402
• Fix OpenSearch AutoTune State Transitions by @silv-io in https://github.com/localstack/localstack/pull/13404
• Remove incorrect deprecation message about USE_SSL by @k-a-il in https://github.com/localstack/localstack/pull/13415
• Lambda/support js 24 by @cloutierMat in https://github.com/localstack/localstack/pull/13410
• fix(lambda): updated error messages for deployment artifacts by @rexchoppers in https://github.com/localstack/localstack/pull/13417

New Contributors

• @jeis4wpi made their first contribution in https://github.com/localstack/localstack/pull/13341
• @purcell made their first contribution in https://github.com/localstack/localstack/pull/13337
• @mboorstin-circle made their first contribution in https://github.com/localstack/localstack/pull/13343
• @YukiMichishita made their first contribution in https://github.com/localstack/localstack/pull/13281
• @rexchoppers made their first contribution in https://github.com/localstack/localstack/pull/13417

Full Changelog: https://github.com/localstack/localstack/compare/v4.10.0...v4.11.0