Stackable

Messaging Experience Platform

Experiences that truly stack up.

Get startedView on GitHub

Extend Zendesk Messenger with rich, interactive extensions enabled by a flexible, AI-native developer platform.

{
  "name": "My Extension",
  "version": "0.1.0",
  "targets": [
    "slot.content"
  ],
  "permissions": [],
  "allowedDomains": []
}

Stackable Labs - Developer Documentation

New: messaging.send capability

Extensions can now send messages directly into the active conversation — text, image, file, and carousel kinds. Pair with the useMessaging hook and see the Messaging Examples cookbook to get started.

What is an "Extension"?

Extensions are micro-apps that extend a customer's messaging experience. They can be published to the marketplace for any customer to install, kept private for your own use, or distributed directly to a single site. Each one is built with React and can deliver anything from a simple badge to a fully interactive multi-page experience!

CLI Quick Start

Local TypeScript project, version-controlled. Best for production extensions and teams.

AI Extension Studio

Build in your browser. No installs, no Node, no tunnel. Helpful for prototyping or first extensions.

Extension "Manifest" Settings

Every extension declares three main things in a "manifest" - and the framework renders them securely at runtime:

  • Surfaces — places in the UI where your extension renders. See Surfaces.
  • Capabilities — host-mediated APIs for reading data, sharing context, and invoking actions. See Capabilities.
  • Instance settings — per-installation configurable fields/settings for your extension, including secure values like API keys. See Instance Settings.

Surfaces declare your real estate, capabilities your reach, and instance settings the configuration each install requires.

AI-Accelerated Development

Stackable's developer tooling is AI-native end to end. AI Extension Studio, Agent Skills, a live MCP server, and a Claude Code plugin all work together to take you from possibility to production in minutes.

Explore all AI tooling options →

Live Development Previews

With the Stackable CLI (@stackable-labs/cli-app-extension), easily build and preview your extension behind a local tunnel. You can visit a site using your extension and see a live preview of your latest code while in development. Full walkthrough in the Quick Start.

Extension Marketplace

Brands across the platform discover your extensions and one-click install them in seconds — an instant addition to their messaging experience. Free for everyone today, with paid extensions and revenue sharing coming soon, so you can build a real business on top of the platform, not just publish to it.

Jump to reference

Quick Start

Create, develop, and deploy your first extension in minutes.

Components

UI component catalog available to extensions via the host rendering pipeline.

Capabilities

Host-mediated APIs for data access, actions, and context.

Patterns

Common extension patterns: store management, API wrappers, surface composition.