A bidirectional bridge that connects Mattermost and Matrix, enabling real-time message synchronization between platforms.

• Bidirectional Sync: Messages, reactions, and edits sync automatically in both directions
• Real Users: Messages appear from actual users, not bots, with authentic names and avatars
• Rich Content: Full support for formatting, emoji reactions, threads, and file attachments
• Easy Setup: Simple configuration with automatic registration file generation
• Secure: Loop prevention, proper authentication, and namespace isolation

• Download from releases
• Upload via System Console → Plugins → Plugin Management

• Go to System Console → Plugins → Matrix Bridge
• Set your Matrix homeserver URL (e.g., https://matrix.example.com)
• Generate Application Service and Homeserver tokens
• Enable message synchronization

• Download the registration file from the admin console
• Add it to your Matrix homeserver's app_service_config_files
• Restart your homeserver

Use slash commands to bridge channels:

/matrix test                            # Test Matrix connection and configuration
/matrix create "Room Name"              # Create new Matrix room
/matrix map #room:matrix.example.com    # Map to existing room
/matrix status                          # Check bridge health

1. Create Mapping: Link a Mattermost channel to a Matrix room
2. Enable Sharing: Configure the channel for shared channels in Channel Settings
3. Start Chatting: Messages automatically sync between platforms with full user attribution

What Gets Synced:

• Messages (with formatting and mentions)
• Emoji reactions (4,400+ emoji support)
• Message edits and deletions
• User profiles with display names and avatars
• Reply threads

• Mattermost Server 10.7.1+
• Matrix homeserver with Application Service support (Synapse, Dendrite, etc.)
• Admin access to both platforms

# Build everything
make all

# Run tests
make test

# Deploy to local Mattermost
make deploy

To generate the emoji mappings in the server/emoji_mappings_generated.go file:

make generate-emoji

For local development and testing, you can run a Matrix Synapse server using Docker Compose.

1. Install and configure the Mattermost Matrix Bridge plugin first
2. Generate the bridge registration file through the plugin configuration
3. Copy the generated registration file to docker/mattermost-bridge-registration.yaml

1. Start the services:

   docker-compose up -d

2. Create an admin user:

   docker exec -it mattermost-plugin-matrix-bridge-synapse-1 register_new_matrix_user -c /data/homeserver.yaml -u admin -p admin123 -a http://localhost:8008

3. The Matrix server will be available at http://localhost:8888

• The Synapse server is configured to use PostgreSQL as the database
• Registration is enabled for development purposes
• App service configuration is loaded from docker/mattermost-bridge-registration.yaml
• Room list publication is restricted to the bridge user only

docker-compose down

To completely reset (remove all data):

docker-compose down -v

Connection Issues:

• Verify Matrix server URL and tokens are correct
• Check that registration file is installed on Matrix homeserver
• Use /matrix status to diagnose problems

Sync Problems:

• Ensure channel is configured for shared channels
• Check that both platforms can reach each other
• Review plugin logs for detailed error information

• GitHub Issues
• Matrix Specification
• Mattermost Plugin Documentation

• Support multiple Matrix instances
• Expose more Share Channels APIs in plugin API
• Improve support for private, encrypted channels

MIT License - see LICENSE file for details.