How to use the .NET AWS SDK with LocalStack.


The AWS SDK for .NET, like other AWS SDKs, lets you set the endpoint when creating resource clients, which is the preferred way of integrating the .NET SDK with LocalStack.


Here is an example of how to create an LambdaClient with the endpoint set to LocalStack.

var lambdaClient = new AmazonLambdaClient(new AmazonLambdaConfig(
        ServiceURL = "http://localhost:4566"

If you want to specify a region and credentials when creating the client, please set them as AuthenticationRegion and BasicAWSCredentials, like in this example:

var lambdaClient = new AmazonLambdaClient(new BasicAWSCredentials("test", "test"), new AmazonLambdaConfig(
        ServiceURL = "http://localhost:4566",
        AuthenticationRegion = "eu-west-1"

S3 specific endpoint

Here is another example, this time with an S3Client and its specific endpoint.

var config = new AmazonS3Config({ ServiceURL = "http://s3.localhost.localstack.cloud:4566" });
var s3client = new AmazonS3Client(config);
var config = new AmazonS3Config(
        ServiceURL = "http://localhost:4566",
        ForcePathStyle = true
var s3client = new AmazonS3Client(config);

Alternative: Using LocalStack.NET

If you’re working with .NET and LocalStack, you have a few options. In addition to the AWS SDK for .NET, there’s an alternative client library, LocalStack.NET, which facilitates integration with LocalStack.


LocalStack.NET is a .NET client library developed to simplify the connection between .NET applications and LocalStack. It wraps around the AWS SDK for .NET and offers an alternative setup for creating LocalStack clients.

LocalStack.NET Documentation: Comprehensive guide and examples here.

How it Works

Instead of manually setting the endpoint configurations when initializing a client, LocalStack.NET offers methods that handle these details. The library aims to reduce the boilerplate required to set up LocalStack clients in .NET.

Example Usage

Dependency Injection Approach

public void ConfigureServices(IServiceCollection services)
    // Add framework services.



var amazonS3Client = serviceProvider.GetRequiredService<IAmazonS3>();

Standalone Approach

var sessionOptions = new SessionOptions();
var configOptions = new ConfigOptions();

ISession session = SessionStandalone.Init()

var amazonS3Client = session.CreateClientByImplementation<AmazonS3Client>();


  • Consistent Client Configuration: LocalStack.NET provides a standardized approach to initialize clients, eliminating the need for manual endpoint configurations.
  • Tailored for .NET Developers: The library offers functionalities specifically developed to streamline integration of LocalStack with .NET applications.
  • Adaptable Environment Transition: Switching between LocalStack and actual AWS services can be achieved with minimal configuration changes when leveraging LocalStack.NET.
  • Versatile .NET Compatibility: Supports a broad spectrum of .NET versions, from .NET Framework 4.6.1 and .NET Standard 2.0, up to recent .NET iterations such as .NET 7.0.


  • Both the standard AWS SDK method and LocalStack.NET provide ways to integrate with LocalStack using .NET. The choice depends on developer preferences and specific project needs.
  • LocalStack.NET works alongside the AWS SDK, using it as a base and providing a more focused API for LocalStack interactions.


Last modified May 17, 2024: Add callout shortcode (#1260) (52d305d4e)