Research on open source team communication tools

This wiki page was created to identify, research, and document open-source team communication & collaboration tools as part of the following task: https://phabricator.wikimedia.org/T179989

Context and qualities

There are many open-source communication and collaboration tools, all with their own unique features or qualities.

Most of them are based on the idea that the freedom to configure your tool can build a more productive team.

Some of them seek to completely reform the typical chat system and push boundaries of what chat service-client can be.

In any case, FOSS software has come a long way and is an alternative to the software behemoths such as Skype or Slack. For those looking for advanced customization of interface with branding or modality of use (connecting to other infrastructure, like Wikimedia), it might also be the only feasible and flexible option.

Zulip

See also: Zulip vs. Mattermost comparison

Zulip is an open-source team communication system acquired by Dropbox in 2014 and released as open-source in 2015. It is created primarily using Python and Javascript (web front end). Zulip's biggest strength is its threaded group conversations which allow people to talk about multiple topics at once without getting lost or overwhelmed.

The user interface of Zulip

Amount of contributors in repositories

zulip/zulip: 547
zulip/zulip-mobile: 60
zulip/zulip-electron (desktop client): 42
zulip/zulip-android: 31

Requirements:

Ubuntu 18.04 Bionic, Ubuntu 16.04 Xenial, Debian 9 Stretch, or Debian 10 Buster
Minimum 2 vCPUs/cores, 2GB of RAM or more and 10GB storage
PostgreSQL 9.1+
SSL certificate and email credentials

Pros

Threaded group conversations
Desktop apps
One-on-one and group private conversations
Inline image, video, and tweet previews
More than 40 integrations
Desktop and Email notifications
Support for Android, iOS, MacOS, Windows, and Linux
33 different language options (including English, Spanish, French, Italian, German, Japanese, Korean, Portuguese, Russian, Arabic, and Chinese translations)

Cons

Lots of bugs still present
Terrible Android and iOS apps

Mattermost

See also: Zulip vs. Mattermost comparison

Mattermost is a team communication system released on June 2015 with an "Enterprise" version and an open-source "Team" version. It is written in Go and React. Mattermost considers itself as an open-source version of Slack. It also has an easy Docker install. Recent server versions support Playbook and KanBan features.

The user interface of Mattermost

Amount of contributors in repositories

Requirements:

Ubuntu 16.04, Ubuntu 18.04, Debian Buster, CentOS 6+, CentOS 7+, RedHat Enterprise Linux 6+, RedHat Enterprise Linux 7+, Oracle Linux 6+, Oracle Linux 7+
MySQL 5.6+ or PostgreSQL 9.4+
Amazon Aurora MySQL 5.6+
1 - 1,000 users - 1 vCPU/cores, 2 GB RAM
1,000 - 2,000 users - 2 vCPUs/cores, 4 GB RAM
Storage: 5-25 MB/user/month

Pros

Self-hosted one-on-one and group messaging, file sharing and search
Native apps for iOS, Android, Windows, Mac, Linux
Unlimited search history & integrations
Easy to use Slack-like user interface
Threaded messaging
Markdown formatting
Access multiple teams from one account
Has a good SDK for plugin creation
Support for Android, iOS, MacOS, Windows, and Linux
Supports 17 different language translations (including English, German, French, Dutch, Italian, Polish, Portuguese, Russian, Spanish, Turkish, Chinese, Korean & Japanese translations)

Cons

Threaded conversation doesn't show that well
Super closed development process
Requires buying a closed-source product past a certain size
Less integrations and plugins than other tools

Rocket.Chat

Rocket. Chat is a webchat server, developed in JavaScript, using the Meteor web framework. It claims to be a great solution for communities and companies wanting to privately host their own chat service or for developers looking forward to building and evolve their own chat platforms.

The user interface of Rocket.Chat

Amount of contributors in repositories

RocketChat/Rocket.Chat: 576
RocketChat/Rocket.Chat.Electron (desktop client): 114
RocketChat/Rocket.Chat.Android: 82
RocketChat/Rocket.Chat.iOS: 54

Requirements

Ubuntu 18.04 LTS (with or without docker)
Node.js 4.5+
MongoDB 2.6+
50-200 users - Single core (2 GHz), 1 GB RAM, 30 GB of SSD
100-500 users - Dual core (2 GHz), 2 GB RAM, 40 GB of SSD
300-1000 users - Intel Xeon E5-2603 v4 (or equivalent), 4 GB RAM, 500 GB hard disk or larger

Pros

Supports a wide variety of authentication methods
Desktop and Email notifications
Ability to share your screen with others
Android and iOS apps
Looks similar to Slack
Very active and helpful community
Supports 22 different languages
Support for Android, iOS, MacOS, Windows, and Linux

Cons

A large number of open issues on GitHub (~1984)
Small annoying bugs appear after long use (web client)

Matrix

See Also: Matrix.org

Matrix is an open protocol for interoperable, decentralized, real-time communication over IP. It can be used to power Instant Messaging, VoIP/WebRTC signaling, and Internet of Things communication between different service providers.

The user interface of Matrix client Riot.im

Amount of contributors in repositories

Requirements

POSIX-compliant system (tested on Linux & OS X)
Python 3.7
PostgreSQL
At least 2 GB of free RAM for the server (and whatever you can add for PostgreSQL to make it happy for real life scenario)

Pros

Open standard protocol specification, REST+JSON interface, a simple bot is a few lines of shell script (a complex bot example)
Does not require a centralized server, distributed design from the ground up, consistent view on every server ("eventually consistent network")
Real security is part of the core protocol: end-to-end encrypted one-to-one or group chats with thousands of participants
Full room history provided by the servers (with various security restrictions)
Supports different kinds of communication (direct messages, group chat, voice group chats, video group conferences [through Jitsi integration], chatlog web pages)
Supports message editing and revocation, supports message reactions (emoticons)
CommonMark formatting, supports syntax highlighting, coloring, file/image attachments
Works like IRC with bouncers
Offers a huge range of different clients
Can be integrated with existing communication services
Authentication methods are pluggable (email, tokens, SSO)
Large number of users (estimated between 100 000 and 3 000 000)

Cons

Documentation is a bit confusing and difficult for a newbie to understand
Is not technically a standalone tool but a protocol (or a distributed database (acyclic graph) of JSON data)
The reference server is written in Python, and faster servers are still in development stage (Rust, C++, Go)
Threading UI is still in design phase

Kontalk

Kontalk is a free community-driven cloud-based instant messaging service. Users can send messages and exchange photos or contacts. Kontalk also provides end-to-end encrypted messaging. Its client-side code is open-source and their network of servers is run by volunteers to provide a stable and secure service for all of users.

The user interface of Kontalk

Amount of contributors in repositories

Requirements

No requirements needed, Kontalk runs on it own network of servers run by volunteers

Pros

Desktop app with multi-platform support
Free of charge, runs on donations
XMPP client protocol
End-to-end-encrypted messaging
Servers can be hosted on its own
Offers 6 different languages (English, German, Italian, Dutch, Serbian, Spanish)
Support for Android, MacOS, Windows, and Linux

Cons

Accounts are bound to phone number, no username
Desktop app runs slow
The desktop app UI looks terrible
Lack of chat features like file sharing
No iOS support

Gitter

Gitter is an open-source instant messaging service. It is designed for developers and tightly integrated with GitHub repositories. It was acquired by GitLab in 2017 and became open source under an MIT license.

The user interface of Gitter

Amount of contributors in repositories

Requirements

No requirements needed; Gitter rooms/communities are hosted on Gitter's servers

Pros

Supports authentication using GitHub or Twitter
Automatically logs all messages in the cloud
Individual chat rooms can be created for individual git repositories on GitHub.
Notifications
Integration with Jenkins and Travis CI
Markdown and KaTeX
Inline media files
Support for Webapp, Android, iOS, MacOS, Windows, and Linux

Cons

Many of its features are tightly integrated with Github (not Gerrit)
Privacy concerns due to logs
Extremely unintuitive design
Supports English only

Discourse

See also: Discourse

Discourse is an open-source open source discussion platform. It claims to completely disrupt the Internet forum idea and intends to improve online discussion quality through its improved software.

The user interface of Discourse

Amount of contributors in repositories

discourse/discourse: 710

Requirements

Ubuntu 18.04 Bionic LTS (At a minimum, a 64-bit Linux OS with a kernel version of 3.10+ is required)
1 GB of RAM for small communities, 2 GB for larger communities

Pros

Trust system to prevent trolls and spammers
Simple
Just in time loading (no next page button)
Dynamic notifications (notifications whenever relevant)
Designed for mobile displays
Integrations with Slack, Google Analytics, Github, Patreon, and more
Social logins
Support for 25 different languages (Hebrew, Spanish, Chinese, French, German, Korean, Arabic, Vietnamese)
Support for Android, iOS, MacOS, Windows, and Linux

Cons

Is a paid service unless self-hosted
Buggy apps
Poor email forwarding

Telegram

The user interface of Telegram (Desktop and Mobile)

Telegram is a cross-platform messaging service. It uses the Internet to send messages and supports group chats, direct replies (which act like threads), and end-to-end encryption for direct messaging.

Clients:

Signal

Signal is a cross-platform encrypted messaging service. It uses the Internet to send one-to-one and group messages, which can include files, voice notes, images and videos. It can also make one-to-one voice and video calls as well as SMS (on Android).

The User Interface of Signal

Amount of contributors in repositories

Requirements

No requirements needed; Signal's servers are supported by a team of developers, community donations, and grants.

Pros

~~Axolotl~~ Signal protocol (Fast and reliable protocol)
Uses existing phone number (No passwords to forget)
Push notifications (using closed vendor services)
Free group, text, picture, and video messages
One-to-one voice and video calls for mobile users
End-to-end encrypted
Supports seven different languages (English, German, Spanish, French, Chinese, Portuguese, Portuguese)
Support for Android, iOS, MacOS, Windows, and Debian-based Linux

Cons

Requires a phone number
Blocked in Iran and Egypt
Clunky official client, no alternative clients
Limited group chat
Open source but almost impossible to install self-hosted version due to a large amount of commercial service dependency

MongooseIM

MongooseIM is a robust and efficient instant messaging platform designed for enterprise use. It is fault-tolerant and can easily scale for more capacity by simply adding a box or VM. MongooseIM can accept client sessions over XMPP, REST API, SSE, Websockets, and BOSH.

Amount of contributors in repositories

Requirements

8GB RAM
2-4 cores
100MB of disk space
*nix OS (CentOS 7, Ubuntu 16.04 LTS (Xenial), Ubuntu 18.04 LTS (Bionic), or macOS 10.14 (Mojave))

Pros

Reliable
Scalable (Add more VM's)
Various Messaging Protocols (XMPP Protocol, Rest API, etc.)

Cons

You have to build your own client
iOS and Android apps are not available on App or Play store