LocalStack Extensions

Manage LocalStack Extensions to add custom functionality, integrate third-party tools, and extend LocalStack capabilities.

Capabilities

• Install and manage LocalStack Extensions
• Discover available extensions
• Configure extension settings
• Develop custom extensions

Extension Management

List Installed Extensions

localstack extensions list

Install Extensions

# Install from PyPI
localstack extensions install localstack-extension-name

# Install specific version
localstack extensions install localstack-extension-name==1.0.0

# Install from Git repository
localstack extensions install "git+https://github.com/org/extension-repo.git"

Uninstall Extensions

localstack extensions uninstall localstack-extension-name

Enable/Disable Extensions

# Extensions are enabled by default after installation
# Disable via environment variable
EXTENSION_NAME_ENABLED=0 localstack start -d

Available Extensions

Community Extensions

Check the LocalStack Extensions Registry for community-contributed extensions.

Using Extensions

MailHog Extension

# Install
localstack extensions install localstack-extension-mailhog

# Start LocalStack
localstack start -d

# Access MailHog UI
open http://localhost:8025

# SES emails will be captured by MailHog
awslocal ses send-email \
  --from sender@example.com \
  --to recipient@example.com \
  --subject "Test" \
  --text "Hello"

Developing Custom Extensions

Extension Structure

my-extension/
├── setup.py
├── my_extension/
│   ├── __init__.py
│   └── extension.py

Basic Extension

# extension.py
from localstack.extensions.api import Extension, http

class MyExtension(Extension):
    name = "my-extension"

    def on_extension_load(self):
        print("Extension loaded!")

    def on_platform_start(self):
        print("LocalStack is starting!")

    @http.route("/my-endpoint")
    def my_endpoint(self, request):
        return {"message": "Hello from extension!"}

Install Local Extension

# Install in development mode
localstack extensions install -e ./my-extension

Configuration

Extensions can be configured via environment variables:

# General pattern
EXTENSION_<NAME>_<SETTING>=value localstack start -d

# Example
EXTENSION_MAILHOG_PORT=8025 localstack start -d

Troubleshooting

• Extension not loading: Check localstack logs for errors
• Conflicts: Disable conflicting extensions
• Version issues: Ensure extension is compatible with your LocalStack version