Getting Started

In this guide we will setup the bridge connected to your homeserver. This guide will walk through the most common settings, other options are documented in the config.sample.yaml file.


These instructions assume you are using Synapse 1.4.0+. They should work for older releases and other homeservers, but configuration may vary.

From source

$ git clone
$ cd Matrix-appservice-slack
$ npm install
$ npm run build

With Docker

$ docker pull matrixdotorg/matrix-appservice-slack:latest

How it Works:

The bridge listens to events using the Slack RTM API over websockets, and to Matrix events on a port that the homeserver sends events to. This tutorial will walk you through configuring your homeserver and Slack to send messages to this bridge and setting up the api so this bridge can relay those message (all messages) to the other bridged channel. For the sake of this tutorial, we will assume your homeserver is hosted on the same server as this bridge at the port 8008 (http://localhost:8008).

If you’ve set up other bridges, you’re probably familiar with the link used to reach your homeserver, the “homeserver url”. This is the same URL. This is the same port. No problem! Multiple bridges can plug into the same homeserver url without conflicting with each other.

NOTE: If your bridge and homeserver run on different machines, you will need to introduce proxying into the mix, which is beyond the scope of these docs. There are some really awesome and kind people in the Matrix community. If you’re ever stuck, you can post a question in the Matrix Bridging room.


  1. Create a new Matrix room to act as the administration control room. Note its internal room ID (Example: !

  2. Decide on a spare local TCP port number to use. It will listen for messages from Matrix and needs to be visible to the homeserver. Take care to configure firewalls appropriately. This port will be notated as $MATRIX_PORT in the remaining instructions.

  3. Create a config/config.yaml file for global configuration. There is a sample one to begin with in config/config.sample.yaml. You should copy and edit as appropriate. The required and optional values are flagged in the config.

  4. For homeserver.server_name, enter the server name, e.g. or localhost.

  5. For db, see datastores on how to set up a database with the bridge.

  6. For matrix_admin_room, enter the internal room ID of the administration control room (Example: !

  7. Generate the appservice registration file. This will be used by the Matrix homeserver. Here, you must specify the direct link the Matrix Homserver can use to access the bridge, including the Matrix port it will send messages through (if this bridge runs on the same machine you can use localhost as the $HOST name):

    $ npm start -- -r -c config/config.yaml -u "http://$HOST:$MATRIX_PORT" or with docker:

$ docker run -v /path/to/config/:/config/ matrixdotorg/matrix-appservice-slack \ 
    -r -c /config/config.yaml -u "http://$HOST:$MATRIX_PORT" -f /config/slack.yaml
  1. Start the actual application service:

    $ npm start -- -c config/config.yaml -p $MATRIX_PORT or with docker:

    $ docker run -v /path/to/config/:/config/ matrixdotorg/matrix-appservice-slack

  2. Copy the newly-generated slack-registration.yaml file to your Matrix homeserver. Add the registration file to your homeserver config (default homeserver.yaml):

    - ...
    - "/path/to/slack-registration.yaml"

Don’t forget - it has to be a YAML list of strings, not just a single string.

Restart your homeserver to have it reread the config file and establish a connection to the bridge.

  1. Invite the bridge bot user into the admin room, so it can actually see and respond to commands. The bot’s user ID is formed from the sender_localpart field of the registration file, and the homeserver’s domain name. For example:


NOTE: At the time of writing, Element does not recognize the Slack bot. This is okay. The bot is there. If Element asks if you’re sure you want to invite @slackbot, just say yes.

The bridge bot will stay offline for most of the time. This is normal. You will know if the bridge is working (and that your homeserver is properly connected) if it accepts your invitation. You can expect the bot to accept within 45 seconds of being invited. If it never accepts the invitation, check your bridge’s logs and review the above steps.

The bridge itself should now be running. Congrats!

To actually use it, you will need to configure some linked channels, see linking channels.

Once a Slack Workspace is connected, you can offer automatic hints on how to bridge existing and new channels by enabling Workspace Sync.


  1. Build the latest version of the application service. Follow the Installation section instructions.
  2. Restart the application service.

Note: You do NOT need to regenerate an appservice registration file.


If you want to host this bridge on a different server than your homeserver, you will have to proxy the bridge so both the Matrix port (specified when creating your registration file through the -u property) and the Slack port (specified by the inbound_uri prefix in your config file) can be reached. This way both the Matrix homeserver and the Slack API can reach your bridge.