Announcing the LocalStack 4.5 Release

Introduction

LocalStack 4.5 is here, bringing a suite of impactful updates designed to streamline your cloud development workflows even further. This release introduces support for AWS Developer Tools, such as CodePipeline, CodeBuild, and CodeDeploy, upgrades AppSync WebSocket behavior to more closely match AWS, and adds new features to our core service providers like API Gateway, RDS, and EC2.

These enhancements reflect our commitment to local-first development with high AWS parity, faster iteration, and easier testing across cloud-native use cases. Start testing the new features today by upgrading your LocalStack environment.

Get your free LocalStack account to access the latest features and enhancements in LocalStack 4.5!

How to upgrade?

To upgrade to LocalStack 4.5 using the LocalStack CLI, run:

localstack update all

If using Docker CLI or Docker Compose, update the Docker image:

docker pull localstack/localstack:4.5.0     # Community Edition
docker pull localstack/localstack-pro:4.5.0 # Pro Edition

Pin version 4.5.0 in your Docker configuration to ensure reproducibility.

What’s new in LocalStack 4.5?

• New CodeBuild provider
• New CodePipeline provider
• New CodeDeploy provider
• Improved AppSync GraphQL WebSockets
• New enhancements in the API Gateway provider
• New enhancements in the RDS provider
• New enhancements in the EC2 provider
• Miscellaneous

New CodeBuild provider

LocalStack now supports AWS CodeBuild, a fully managed continuous integration service that compiles source code, runs tests, and produces deployable artifacts. This allows you to build and test applications locally with a build process that closely mirrors real AWS environments.

With LocalStack’s CodeBuild provider, you can run builds using source code stored in S3, configure IAM roles and permissions, and output build artifacts to target buckets. The CodeBuild agent runs inside a Docker container and supports a subset of AWS’s standard build environments. Supported APIs are listed on the API coverage page.

Learn more about LocalStack’s CodeBuild provider in the documentation.

New CodePipeline provider

LocalStack now supports AWS CodePipeline, a continuous integration and continuous delivery (CI/CD) service for automating the build, test, and deployment stages of software release workflows. This lets you emulate end-to-end pipeline executions locally using real AWS-style declarations and resources.

LocalStack’s CodePipeline provider uses a custom execution engine that supports multiple action types such as S3 source and deploy, CodeBuild integration, and CodeConnections with GitHub. It allows you to define pipeline stages and actions in JSON format and test the flow from source to deploy. Supported APIs and actions are listed on the API coverage page.

Learn more about LocalStack’s CodePipeline provider in the documentation.

New CodeDeploy provider

LocalStack now includes support for AWS CodeDeploy, a service for automating application deployments to various compute targets like EC2, Lambda, and ECS. With CodeDeploy, you can define applications, configure deployment groups, and emulate deployment flows on your local machine for integration testing or pipeline orchestration.

LocalStack supports the main CodeDeploy API operations such as creating applications, deployment configurations, deployment groups, and deployments. These operations behave similarly to AWS but are fully mocked. Supported APIs are listed on the API coverage page.

Learn more about LocalStack’s CodeDeploy provider in the documentation.

Improved AppSync GraphQL WebSockets

AppSync’s WebSocket behavior has been enhanced to better align with AWS. This includes:

• Full support for AWS-style payload shapes
• Improved lifecycle handling of GraphQL subscriptions

Learn more about AppSync in the LocalStack documentation.

New enhancements in the API Gateway provider

LocalStack’s API Gateway provider now includes the following enhancements for REST APIs:

• Emulation of Canary Deployments, allowing staged traffic shifting strategies for safer releases and A/B testing.
• Support for Response Overrides from Request Templates, enabling more flexible response handling.
• Improved VTL (Velocity Template Language) support, including bracketed expressions and variable assignments in #set operations, increasing compatibility with complex mapping templates.

New enhancements in the RDS provider

LocalStack’s RDS provider now includes the following enhancements:

• Support for PostgreSQL 17, with the default engine version updated to 17.5.
• Support for DB Proxy Endpoints, allowing you to create, describe, and delete DB proxy endpoints for more accurate application emulation. These operations are currently mocked.
• Support for the ManageMasterPassword API, enabling automated credential management and secure DB credential flows.
• Engine Parameter Introspection using DescribeEngineDefaultParameters and DescribeEngineDefaultClusterParameters, allowing you to examine default settings for supported RDS engines.
• Introduction of RDS_PG_MAX_CONNECTIONS environment variable to control the maximum number of connections for PostgreSQL instances.

New enhancements in the EC2 provider

LocalStack’s EC2 provider now includes the following enhancements:

• Support for the GetSecurityGroupsForVpc API, allowing you to retrieve security groups associated with a specific VPC.
• Improved filtering behavior in EC2’s DescribeAvailabilityZones, aligning more closely with AWS behavior.

Miscellaneous

• LocalStack Replicator now supports cross-account VPC replication scenarios using AWS Resource Access Manager (RAM), enabling more realistic testing of multi-account network setups.
• Partial support for the UpdatePipe API is now available in EventBridge Pipes. Currently, only source parameters of an existing pipe can be updated.
• DynamoDB Streams now properly redirects requests for global table replicas to the original region, ensuring consistent stream behavior across all replicas.
• EKS provider now integrates with autoscaling and security groups, allowing you to emulate Kubernetes clusters with more realistic networking and scaling behavior.
• CloudFormation resource AWS::Lambda::Version now supports the ProvisionedConcurrencyConfig property to enable emulation of cold start mitigation strategies.
• Enhanced Lambda GetFunction API parity by returning the reserved_concurrent_executions parameter in responses, allowing you to inspect and manage reserved concurrency settings for Lambda functions.
• Support for the ListRuleNamesByTarget API in EventBridge, allowing you to inspect which rules are targeting a given resource.
• Support for pagination and filtering parameters when listing S3 buckets, improving performance and aligning with AWS behavior in larger S3 environments.
• Support for DeleteDistribution API in CloudFront Lambda@Edge to achieve better parity with AWS.
• Support for DescribeCapacityReservation API in Elastic Load Balancing, allowing you to inspect capacity reservations for load balancers.
• Support for selecting the Scala-based Kinesis mock engine via the KINESIS_MOCK_PROVIDER_ENGINE environment variable (node or scala) for improved performance with large or high-throughput requests.

Conclusion

The LocalStack 4.5 release significantly boosts our mission to bring production-like AWS behavior to your local machine. With major updates across developer tooling, API Gateway, AppSync, RDS, and infrastructure services, this release gives developers more power, precision, and speed.

Upgrade to LocalStack 4.5 today to test faster, reduce cloud friction, and unlock local-first development workflows at scale.