name: localstack-extensions
description: Manage LocalStack Extensions. Use when users want to install, uninstall, list, or configure LocalStack extensions, or develop custom extensions to extend LocalStack functionality.

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 [email protected] \
  --to [email protected] \
  --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