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Slack Bridge

Connect Slack workspaces to Matrix using mautrix-slack.

Features​

  • Full puppeting - Appear as yourself in Slack
  • Channels - Bridge public and private channels
  • DMs - Bridge direct messages
  • Threads - Maintain thread context
  • Reactions - Emoji reactions both ways
  • Files - Share files across platforms
  • User presence - See online status

Docker Setup​

docker-compose.yml
version: '3'
services:
  mautrix-slack:
    image: dock.mau.dev/mautrix/slack:latest
    restart: unless-stopped
    volumes:
      - ./slack-data:/data

Configuration​

config.yaml
homeserver:
  address: https://matrix.example.com
  domain: example.com

appservice:
  address: http://localhost:29335
  hostname: 0.0.0.0
  port: 29335
  database:
    type: postgres
    uri: postgres://user:pass@localhost/slack?sslmode=disable

bridge:
  username_template: "slack_{{.TeamID}}_{{.UserID}}"

  # Double puppeting
  double_puppet_server_map:
    example.com: https://matrix.example.com
  login_shared_secret_map:
    example.com: "your-shared-secret"

  # Encryption
  encryption:
    allow: true
    default: true

  permissions:
    "*": relay
    "example.com": user
    "@admin:example.com": admin

Logging In​

  1. DM @slackbot:example.com
  2. Send !slack login
  3. Follow OAuth flow or use token

Token Login​

Get a user token (xoxc-):

  1. Open Slack in browser
  2. Open DevTools → Network
  3. Look for requests with token parameter
  4. Copy the xoxc- token
!slack login-token xoxc-your-token-here
warning

Token method requires additional cookies. See docs for details.

Bridging Channels​

Auto-Bridge​

Configure automatic bridging:

bridge:
  backfill:
    enable: true
    messages: 100

Manual Bridge​

In the Slack channel on Matrix:

!slack bridge

Commands​

CommandDescription
!slack helpShow help
!slack loginStart login
!slack logoutDisconnect
!slack pingTest connection
!slack syncSync workspaces

Threads​

Slack threads appear as Matrix threads when supported:

bridge:
  threads:
    enabled: true

Troubleshooting​

Rate Limiting​

Slack has strict rate limits:

  • Wait and retry
  • Reduce sync frequency
  • Use fewer concurrent bridges

Token Expired​

Re-login with !slack login or get a new token.

Missing Channels​

  • Check workspace permissions
  • Verify channel visibility
  • Run !slack sync

Resources​

Next: IRC Bridge →