Slack apps are built to extend and enhance the capabilities of the Slack platform, offering seamless integration with workflows, external tools, and custom business logic. Understanding the architecture of a Slack app helps in designing scalable, efficient, and user-friendly applications. Here’s a breakdown of the key components:
1. Slack App Components
- Slack API: Core interface for sending/receiving data (Web API, Events API, RTM API).
- App Manifest: Defines app capabilities, scopes, features (like slash commands, bot tokens).
- Bot User: A programmatic user that interacts with users, channels, and external APIs.
- Slash Commands: Custom commands triggering HTTP requests to your backend.
- Event Subscriptions: Listens to specific events in Slack (like message_posted).
- Interactivity (Modals & Buttons): Handles user interactions via payloads sent to your backend.
- Home Tab: Custom, dynamic app UI for each user within Slack.
2. App Hosting & Backend
- Hosted on a server or cloud function (Node.js, Python, etc.).
- Listens to incoming requests from Slack (events, commands, interactivity).
- Can connect to databases or third-party APIs.
- Uses OAuth 2.0 for authentication and permission scopes.
3. Security & Permissions
- Scopes define what the app can access (e.g.,
channels:read,chat:write). - Tokens (User Token / Bot Token) are used to authenticate API requests.
- Verification tokens or signing secrets ensure the authenticity of requests.
4. Deployment & Installation
- Slack apps are installed per workspace.
- After user authorization, a token is exchanged and stored for future calls.
- Apps can be distributed publicly via the Slack App Directory or kept private.
