A single-user bridge service that automatically cross-posts from your Bluesky account to your Mastodon account. Built specifically for Val.town with TypeScript and Deno.

• Connects your accounts: Securely links your Bluesky and Mastodon accounts using OAuth
• Automatic syncing: Checks for new Bluesky posts every 15 minutes and cross-posts them to Mastodon
• Smart transformations: Converts Bluesky mentions (@handle.bsky.social) to profile links since they don't exist on Mastodon
• Media support: Uploads images and videos from Bluesky to your Mastodon instance
• Duplicate prevention: Tracks synced posts to avoid posting the same content twice
• Error handling: Retries failed posts and logs errors for troubleshooting

✅ OAuth authentication for both Bluesky and Mastodon
✅ Media cross-posting (images & videos)
✅ Mention transformation (handles → profile links)
✅ Duplicate prevention via content hashing
✅ Retry mechanism with exponential backoff
✅ Error logging and sync tracking
✅ Setup wizard for easy configuration

Copy all files from this repository into your Val.town account. The project structure should look like:

├── backend/
│   ├── index.ts              # Main HTTP handler
│   ├── database/
│   ├── routes/
│   └── services/
├── cronjob.ts                # Cron job for syncing
├── frontend/
│   └── index.html            # Setup wizard UI
└── shared/
    └── types.ts              # Shared interfaces

HTTP Trigger (for the web interface and API):

• Set backend/index.ts as an HTTP val
• This serves the setup wizard and handles OAuth callbacks

Cron Trigger (for automatic syncing):

• Set cronjob.ts as a Cron val
• Schedule: */15 * * * * (every 15 minutes)
• For paid accounts, you can use shorter intervals like */5 * * * * (every 5 minutes)

Set these environment variables in your Val.town account:

ATPROTO_CLIENT_ID=https://your-val-url.web.val.run/client-metadata.json

You'll also need to create a client-metadata.json file (see OAuth setup below).

Create a client metadata file at the root of your val that's accessible via HTTP:

{
  "client_id": "https://your-val-url.web.val.run/client-metadata.json",
  "client_name": "ATProto to Fediverse Bridge",
  "redirect_uris": [
    "https://your-val-url.web.val.run/api/oauth/atproto/callback"
  ],
  "scope": "atproto",
  "response_types": ["code"],
  "grant_types": ["authorization_code", "refresh_token"],
  "token_endpoint_auth_method": "none",
  "dpop_bound_access_tokens": true
}

The service automatically registers with your Mastodon instance during setup - no manual configuration needed.

1. Visit your HTTP val URL (e.g., https://your-val-url.web.val.run)
2. Click "Get Started" to begin the setup wizard
3. Connect your Bluesky account by entering your handle
4. Connect your Mastodon account by entering your instance URL
5. Complete the setup

Once configured, the service runs automatically:

1. Every 15 minutes (or your configured interval), the cron job runs
2. It fetches new posts from your Bluesky account
3. Transforms the content (mentions become profile links)
4. Uploads any media to your Mastodon instance
5. Creates the cross-post on Mastodon
6. Logs the result for your review

✅ Included:

• Regular posts with text
• Posts with images/videos
• Posts with links and hashtags
• Posts with mentions (converted to profile links)

❌ Excluded:

• Replies to other posts
• Empty posts
• Posts you've already cross-posted

Visit your val's dashboard to see:

• Setup status and account connections
• Recent sync activity and statistics
• Error logs for troubleshooting
• Post sync history

• Free Val.town accounts: 15-minute minimum sync interval
• Bluesky media limits: 1MB images, 100MB videos
• Mastodon compatibility: Works with all Mastodon instances
• Single user: Designed for personal use (one Bluesky → one Mastodon)

OAuth failures: Check your client metadata URL is publicly accessible
Sync not working: Verify both accounts are connected in the dashboard
Missing posts: Check the sync logs for specific error messages
Media upload fails: Bluesky/Mastodon may have different file size limits

• All tokens are stored encrypted in SQLite
• No data leaves your Val.town instance
• OAuth follows security best practices
• You can revoke access anytime from your account settings

This is an open-source project. For issues or feature requests, check the repository or Val.town community forums.

Built with ❤️ for the decentralized social web