Social Cross-Poster

A Deno-based service that automatically cross-posts messages from Slack to multiple social media platforms (X/Twitter and Nostr) while maintaining user privacy through alias generation.

Features

• Cross-posts messages from a specified Slack channel to:
• X (formerly Twitter)
• Nostr
• Automatically replaces Slack user mentions with randomly generated aliases
• Maintains consistent aliases across posts using Redis
• Provides posting status feedback in Slack message threads
• Handles rate limiting and duplicate post detection
• Auto-refreshes social media tokens when needed

Prerequisites

• Deno 2.x or higher
• Redis server
• Slack workspace with admin access
• X (Twitter) developer account
• Nostr private key (nsec)

Environment Variables

Create a .env file with the following variables:

# Slack
SLACK_USER_TOKEN=xoxp-...
SLACK_CHANNEL_ID=C...

# Twitter/X
TWITTER_CLIENT_ID=...
TWITTER_CLIENT_SECRET=...

# Nostr
NOSTR_NSEC=...

# Redis
REDIS_URL=redis://localhost:6379

Setup

1. Clone the repository:

git clone
cd social-cross-poster

2. Install dependencies:

deno cache main.ts

3. Set up Twitter authentication:

deno run --allow-net --allow-env --allow-read=.env tools/twitter-auth.ts

Follow the authorization flow and save the tokens in Redis.

4. Start the service:

deno task start

Or for development with auto-reload:

deno task dev

Docker Support

Build and run using Docker:

docker build -t social-cross-poster .
docker run -d --env-file .env social-cross-poster

Architecture

The service is built with a modular design, allowing easy addition of new social platforms:

• SocialClient: Abstract base class for social media platforms
• Platform-specific implementations:
• TwitterClient: Handles X/Twitter posting with token refresh
• NostrClient: Manages Nostr event creation and publishing

Redis is used for:

• Storing user aliases
• Tracking the last processed message timestamp
• Managing Twitter OAuth tokens

Contributing

Contributions are welcome. Please open an issue or submit a pull request.

License

MIT