Browser plugin to redirect AWS service calls to LocalStack


LocalSurf is a Chrome browser plugin to repoint AWS service calls to LocalStack. While developing and testing AWS cloud Web applications locally with LocalStack, we need to make the browser connect to the local endpoint (http://localhost:4566) instead of the AWS production servers (*.amazonaws.com). LocalSurf enables you to use the production code without changes, and have the browser make requests to LocalStack instead of AWS directly by explicitly setting the endpoint attribute in the AWS JavaScript SDK.

This plugin is experimental and still under active development. Please report any issues or feature requests on our GitHub repository.


This extension is not yet available in the Chrome Web Store, but can be installed directly from source. Clone the repository on your local machine to get started:

$ git clone git@github.com:localstack/local-surf.git

Head over to chrome://extensions/ in Chrome, then select "Load unpacked" and point to the directory where the source code files are stored on the disk.

Once installed, a new icon should appear in the Chrome extensions bar. When clicking on the icon, the plugin can be enabled/disabled by toggling the Enable local mode checkbox.


To illustrate how the plugin works, we use the AWS Serverlesspresso sample application. This app consists of various backend components (e.g., DynamoDB tables, Lambda functions, Cognito user pools, etc), as well as a hosted Web app user interface (UI) that can be used to interact with the backend components.

We can deploy the backend components to LocalStack directly, using the samlocal command line interface (CLI):

$ samlocal build
$ samlocal deploy

Once deployed, the samlocal CLI will print out a display app URL which will look similar to the following:

Key                 DisplayAppURI
Description         The URL for the Display App
Value               https://workshop-display.serverlesscoffee.com/?region=us-east-1&userPoolId=us-east-1_43c9800e64c84467aa0abdb102e226ef&userPoolWebClientId=vr9aw2jr7iv36ezwaaqlzzkvbp&poolId=us-east-1:95dc88d0-1029-48fe-ba7b-1e6a9741bfc5&host=localhost.localstack.cloud&orderManagerEndpoint=https://fapencq0ue.execute-api.amazonaws.com:4566/Prod&APIGWEndpointValidatorService=https://psmdc7b1lv.execute-api.amazonaws.com:4566/Prod&APIGWEndpointConfigService=https://hw7yw61ba7.execute-api.amazonaws.com:4566/Prod

We can then open the URL in the browser and confirm the configurations in the form dialog:

Once confirmed, we are being forwarded to a signin screen, which uses an AWS Cognito user pool to manage authentication:

After clicking **Sign In** in this form, we can see that the browser makes a request to LocalStack (to `localhost.localstack.cloud`, which is a domain name that resolves to ``).

This sample demonstrates how we can take an existing Web application, without any modification, and make it talk to the LocalStack APIs directly from the browser via the LocalSurf plugin.


Use this extension at your own risk - it is provided on an as-is basis, without warranties or conditions of any kind. In particular, it is your obligation to ensure that the use of this extension is compliant with the user license agreement and the terms & conditions of Amazon Web Services (AWS) and their services.