A terminal client for the Mattermost chat system
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Jonathan Daugherty d87b96f2cd README: add note about twitter account 4 years ago
docs bulk-channel-fetching: whitespace 5 years ago
logo Added icon+logo in SVG format as well as small PNG icons 6 years ago
screenshots Added screenshot of Matterhorn in action 5 years ago
scripts Add a figlet script 5 years ago
setup setup_linux.sh: add package installation command for Fedora 4 years ago
src Merge feature/theme-files 4 years ago
test Types.Posts: explicit export list 5 years ago
.gitignore Add _darcs directory to .gitignore. 5 years ago
.travis.yml Revert "Testing GHC version bump" 5 years ago
AUTHORS.txt package: move/update author list 5 years ago
CHANGELOG.md CHANGELOG: mention theme customization 4 years ago
LICENSE Basic data structures in place for viewing 6 years ago
PRACTICES.md PRACTICES: add link to wiki 5 years ago
README.md README: add note about twitter account 4 years ago
RELEASES.md RELEASES: add host list 4 years ago
Setup.hs add Setup.hs for cabal check 6 years ago
cabal.project.travis travis: Enable -Werror 5 years ago
install.sh install.sh: better workflow for falling back to master on dependency clones 4 years ago
logo.png Move logo image into repository 6 years ago
matterhorn.cabal Merge feature/theme-files 4 years ago
mkrelease.sh mkrelease.sh: use correct bindist file extension (fixes #295) 5 years ago
run.sh run.sh: whitespace 5 years ago
sample-config.ini sample config: expand on relative path handling for theme customization files 4 years ago



Matterhorn is a terminal client for the Mattermost chat system.

New Release Notifications

Get notified about new Matterhorn releases by following our Twitter account!


Quick Start

We provide pre-built binary releases for some platforms. Please see the release list to download a binary release for your platform that matches your server version:


To fetch a release and run Matterhorn, run the following commands (where VERSION and PLATFORM match your setup):

wget https://github.com/matterhorn-chat/matterhorn/releases/download/<VERSION>/matterhorn-<VERSION>-<PLATFORM>.tar.gz
tar xf matterhorn-<VERSION>-<PLATFORM>.tar.gz
cd matterhorn-<VERSION>-<PLATFORM>

When you run Matterhorn you’ll be prompted for your server information and credentials. At present matterhorn supports only username/password authentication.

Note: Version ABBCC.X.Y matches Mattermost server version A.BB.CC. For example, if your Mattermost server version is 3.6.0 then you would download matterhorn version 30600.2.4. See Our Versioning Scheme for details.


For configuration options you have two choices:

  • Interactive configuration entered on each program run
  • Configuration via stored settings in a config file

The first option is useful when trying out the program because you can get up and running without worrying about making a configuration. Once you’re ready to make your settings persistent, they can be added to a configuration file. An example configuration file can be found at sample-config.ini. Any settings omitted from the configuration will be obtained interactively at startup.

When looking for configuration files, matterhorn will prefer config.ini in the current working directory, but will look in the typical XDG configuration directories (you’ll probably want to use $HOME/.config/matterhorn/config.ini) and as a last resort look for a globally-accessible /etc/matterhorn/config.ini.

Using the Client

The user interface has three main areas:

  • Left: list of channels you’re in, and list of users in your team and their statuses (+ means online, - means away, and an absent sigil means offline)
  • Right: messages in the current channel
  • Bottom: editing area for writing, editing, and replying to messages

You can use built-in keybindings or /cmd-style commands to operate the client. To see available keybindings and commands, use the default binding of F1 or run the /help command. Keybindings may include modifiers such as Control (indicated with a C- prefix) or Meta (indicated with a M- prefix). If your keyboard has an Alt key, that will work as Meta. If it does not, you may be able to configure your terminal to provide Meta via other means (e.g. iTerm2 on OS X can be configured to make the left Option key work as Meta).

To join a channel, use the /join command to choose from a list of available channels. To create a channel, use /create-channel. To leave a channel, use /leave-channel.

To create a private group chat amongst yourself and other users, use the /group-msg command, e.g., /group-msg user1 user2.

To see the members in the current channel, use the /members command.

To send a message, type it into the editor and press Enter to send. To send a multi-line message, toggle multi-line mode with the default binding M-e. Markdown syntax is accepted.

To edit your current message in an external editor ($EDITOR), use the default binding of M-k.

To preview the message you’re about to send (e.g. to check on how your Markdown syntax will be rendered), toggle preview mode with the default binding M-p.

To change channels, use /focus or one of the default bindings C-n (next channel), C-p (previous channel), C-g (fast channel switch).

To directly message another user, use /focus or C-g.

C-g channel switching mode does a substring match of the input text on the channel and usernames; metacharacters ^ and $ at the beginning or end of input, respectively, anchor the match in case of multiple matches. The cursor in this mode is usable with C-n and C-p.

To switch to the channel you were in prior to the current channel, use the default binding M-s (swap). The most recent channel is marked in the channel list with a “<” indicator.

To switch to the next channel with unread messages, use the default binding M-a.

To quickly show a list of URLs mentioned in the current channel and then open one in your local browser, use the default binding of C-o and configure the urlOpenCommand configuration setting.

To edit, delete, flag, or reply to a message, select a message with the default binding of C-s. Use the default binding of C-c to cancel these operations.

Messages that have been flagged can be viewed with either the /flags command or M-8. This view allows you to select and unflag particular messages, as well.

To enable spell-checking in the message editor, install Aspell and set enableAspell to True in your configuration. To override Aspell’s choice of master dictionary, set the aspellDictionary option to the name of the dictionary you’d like to use.


  • Channel creation, deletion, and membership management commands
  • Optimized channel-switching modes: M-a, M-s, and C-g
  • Message posting, editing, replying, and deletion
  • Markdown rendering
  • Convenient URL-opening with local browser
  • Secure password entry via external command (e.g. OSX keychain)
  • Yank verbatim content from messages into the system clipboard
  • Preview message rendering before sending
  • Optional smart quoting for efficient Markdown entry
  • Edit messages with $EDITOR
  • Message editor with kill/yank buffer and readline-style keybindings
  • Tab-completion of usernames, channel names, and commands
  • Spell-checking via Aspell
  • Syntax highlighting of fenced code blocks in messages (works best in 256-color terminals)
  • Flagging and unflagging of posts, which are then viewable with M-8 or /flags
  • Support for SOCKS 4 and 5 proxies via the ALL_PROXY, HTTP_PROXY, and HTTPS_PROXY environment variables. (Plain HTTP proxies are not yet supported.)

Spell Checking Support

Matterhorn uses aspell to perform spell-checking of your message input. To use this feature:

  • Install aspell and ensure that your installation includes dictionaries corresponding to your LANG setting. To check this, ask aspell to check some input: $ echo stuff | aspell -a Error: No word lists can be found for the language "en". $ echo $LANG en_US If Aspell succeeds, the output will look like this: @(#) International Ispell Version 3.1.20 (but really Aspell *
  • Set enableAspell to True in your config.ini
  • Enter any message input in the message editor in matterhorn. After a short delay after you stop typing, misspelled words will turn red.


matterhorn is built with the provided install.sh script, which requires git and an appropriate ghc/cabal installation. (Although the name suggests installtion, this will just do a build in dist-newstyle.) This script will pull the appropriate repos and build the application. This is required for building Matterhorn since clones of some of our other dependencies may need to be locally available in deps/ in case important changes to those dependencies have not yet been released.

Our Versioning Scheme

Matterhorn version strings will be of the form ABBCC.X.Y where ABBCC corresponds to the Mattermost server version supported by the release. For example, if a release supports Mattermost server version 1.2.3, the ABBCC portion of the matterhorn version will be 10203. The X.Y portion of the version corresponds to our own version namespace for the package. If the server version changes, X.Y SHOULD be 0.0. Otherwise the first component should increment if the package undergoes major code changes or functionality changes. The second component alone should change only if the package undergoes security fixes or other bug fixes.


If you decide to contribute, that’s great! Here are some guidelines you should consider to make submitting patches easier for all concerned:

  • If you want to take on big things, let’s have a design/vision discussion before you start coding. Create a GitHub issue and we can use that as the place to hash things out. We’ll be interested to discuss any usability / UI, performance, or compatibility issues.
  • Please make changes consistent with the conventions already used in the codebase.
  • We follow a few development practices to support our project and it helps when contributors are aware of these. Please see PRACTICES.md for more information.

Frequently Asked Questions

  • Q: Does matterhorn support Gitlab authentication?
  • A: No. But we would be happy to work with contributors who are interested in investigating what this would take and/or implementing it. See the Contributing section for details.