6 Top open source team chat software for self hosted environment

Are you looking for the best open-source team chat software solution as a Slack alternative? Those help to create a collaborative environment in an office or enterprise, then you are at the right place…

Verbal communication is in society since the inception of the period when humans found a way to express feelings in words/sound. This communication wasn’t only limited to the verbal mode it later came on paper and then on computers. The value of good communication has its own significant place not only professionally but in personal life too.  However, here we only talk about professionals.

Now, the enterprises or businesses are not confined to only small spaces or tracts, they are spreading their arms and legs in multiple directions to achieve targeted growth. In such a scenario, the chatting among the company’s employees working on some particular project is either on email or some public chatting applications. But from the perspective of security and exchange of sensitive over a public chatting platform such as WhatsApp would not be a wise idea.

The office team chat software should be in the control of businesses or teams using them for some project. Where they can add different features as required, such kinds of needs can be fulfilled by the open-source collaboration group chat platforms without the interface of any third party. However, while implementing self-hosted open-source team chat servers or applications for the team make sure that they are behind a firewall for enhanced security.

Here are some top open source Group Chat software as a self-hosted team chat solution. 

Zulip- team chat platform

Zulip team chat platform which is one of the great & best alternatives to Slack/HipChat software was a proprietary software in its incubation days. It was developed by a startup called Zulip. However, later Dropbox acquired it and in 2015 publicize the code under the Apache license. It is now available as an open-source project on Github.

They also offer the same project pre-hosted along with support for those who don’t have the technical expertise or want to self-host the project.

Zulip open source web chat server offers a beautiful interface, chatting system along with emoji support for discussing math with LaTeX. It automatically generates a preview of links (image, video & tweet previews) while sending them. Drag and drop facility for a file into the compose box is available too.

Zulip open source team chat platform

If you are using this team chat software for some software development project then it is possible to discuss code using Markdown code blocks (and syntax highlighting) and discuss blocks of text with block quotes.

Other features are @-mentions support, LDAP/Active Directory support, Stream-wide announcements, Desktop notifications, Audible notifications, Emails for important missed messages, Alert words, support keyboard shortcuts, different integrations, API, and more…

From a security point of view, it supports single sign-on with Google, GitHub, and Active Directory/LDAP. They also working on integrating SAML authentication systems, administrators can deactivate any user, bot, or integration;  know more at Zulip official website.

The client app for Zulip team chat software is available for Windows, Linux,  macOS, Android, and iOS.

Project Files at Github



Rocket. Chat can also be considered as a nice Slask alternative team chat software solution. It is a free and open-source (MIT license) real-time team chat server and client model application. The server part of the Rocket can be easily installed on Debian or REHL based operating system while the RocketChat client is cross-platform and available for Android, iSO, Windows, Linux, and macOS.

Rocketchat open source live chat server alternative to slack

RocketChat developed on Meteor framework and written in CoffeeScript and JavaScript. The developers of RocketChat offered cloud hosting as well as the provision to host their server application on self-owned servers or hosting.

This open-source web chat service is not limited only to live individual or group chatting (typing) but also to audio and video conferences facilities are available too. For security two-factor authentication (2FA), E2E encryption, SSO, and dozens of OAuth providers support. Apart from this guest access, desktop notifications, searches,  screen sharing, file sharing, LiveChat, and LDAP Group Sync are also there.

On Meteor framework developed RocketChat, also provides good customization options via WebHook integrations, Themes to personalize UI, REST API, LiveChat API or Real-time API, data importers for Slack and HipChat users, Marketplace to install apps to functions expansion and plugin to integrate RocketChat features into popular applications such as Drupal or Pidgin.

If you have a team of different language speaking, the RocketChat also has the solution for that by providing a feature called Real-time translation. It automatically translates the message in realtime between users and supports over 50 languages. User can experience it before installing, here is the RocketChat Demo

To test Rocket. Chat open source team chat software locally on Ubuntu 19.04 see: Rocket chat server and client installation on Ubuntu 

Rocket.Chat website


Mattermost Team chat

Mattermost is another open-source team chat software for enterprises and offices. The developers of Mattermost marketed it as the best open-source alternative to Slack and HipChat. Like Rocket.Chat, they also offer both cloud-hosted as well as the software itself for the public to download and create self-hostable chat service.

Mattermost Team chat + office chat software claternative to slack

It designed especially keeping in mind to fulfill the internal demands of chatting and communication of organizations and companies.

However, the Mattermost was not always an open-source application. Its codes initially were proprietary and the application itself used as an internal chat tool in a game studio known as SpinPuch. But later become open source under MIT License for server-side application and Apache License 2.0 for the rest.

It is developed over React-framework using Golang and JavaScript languages. The client application of Mattermost is also cross-platform and available for Windows, macOS, Linux, iOS, and Android.

As Mattermost considering itself an open-source slack alternative, it doesn’t mean it just bosting off, there are very convincing features that prove that. Such as real-time voice, video and screen sharing, public and private chat along with emoji and rich formatting.

The message history is also fully searchable and multi-language support (U.S. English, Chinese (Simplified & Traditional), Dutch, French, German, Italian, Japanese, Korean, Polish, Brazilian Portuguese, Russian, Turkish, Spanish, and Ukrainian) is also there. Users can share files, audio, images, and links over the chat even from mobile devices.

Furthermore, Mattermost Team Edition open source “virtual office” chat software provides tools for custom branding, customizable third-party bots, integrations, and command-line tools, webhooks, APIs, drivers, and third-party extensions.

Get the Mattermost Team Chat- Download 


Let’s Chat

Another office chat or team chat software under MIT license developed on Node.js platform and comes with many familiar features like Slack. This is basically a chat app for small teams.

Let’s Chat team chat app

It is also self-hosted open-source team chat software that features: LDAP / Kerberos Authentication,  XMPP Multi-user chat (MUC), provides multiple rooms useful when different working separately on some project within the organization. These rooms are Private / Password-protected.

The user can enable Desktop Notifications for the coming messages, @Mentions possible while chatting. In addition to this image embeds, file uploads (Local / Amazon S3 / Azure), Hubot Friendly,  REST-like API to connect it with other tools, and  Transcripts / Chat History like features are on Let’s Chat.

Security Compass developed Let’s Chat is a Multilingual group chat software that can be easily installed on Linux using NPM or using Docker/Vagrant

Let’s Client app is available for Android and iOS while for Windows/Linux/macOS the web interface.

Get the Let’s Chat files from Github to install.



Matrix.org provides a complete decentralized open-source platform that comprises Matrix servers, clients, and other services licensed under the Apache License. It uses lightweight protocols to provide real-time communication.  The main gist behind the Matrix design is to provide a common place or service to allow users to communicate not only with each other using Matrix supported client chat apps; but also with different other service providers via online chat, voice over IP, and video telephony.

Matrix chat server

The companies about to set up a team chat on Matrix can either use the open decentralized Matrix.org servers via team chat client software like Riot.im or download the Matrix Synapse server project for creating a self-hosted Matrix server.

It provides real-time communication and can integrate with standard web services via WebRTC to allow the chat via browser-to-browser applications.

Furthermore, it also supports the bridge messaging system to allow sync messages between Matrix and different chat application systems or non-matrix servers. For example, suppose there is a Matrix channel called #h2smedia which bridged with other h2smedia channels on non-matrix servers such as Telegram and Slack. So, once we successfully create a bridge between them, the message generated on a system goes from one system to all other bridge systems such as from Telegram to Matrix to Slack and vice versa, this ensures that all channels received the same messages and always in sync situation.

Basically, bridges act as relays those ensure posted message in one account should be visible in other non-matrix accounts. Currently, Matrix offers bridges for Telegram, Discord, Gitter, Slack/Mattermost, IRC, Rocket. Chat, Whatsapp,  XMPP, and more. See the complete list of Matrix bridge project.



In a list of open-source team chats software, how could we forget the Riot.im, another runner up as a slack alternative in the open source category.  This free office chat software based on Matrix protocol to effectively establish communication between different teams working together.

Riot.im basically just provides a chatting application interface to connect the decentralized Matrix.org secure servers. It provides WebRTC and available as a client application for Windows, Linux, macOS, Android, and iOS.

Riot.im open source team chat application

Few Features:

  • Voice & Video Conferencing
  • Drag-and-drop for quick sharing, and browse archives or search for files
  • Receive notifications whenever anyone mentions your name, and define keywords
  • Apps, Stickers, Widgets & Bots
  • Theme based customization
  • end-to-end encryption via matrix
  • Bridge other apps and networks

Download Riot.im or use browser app

So, these are a few well-known Team chat collaboration software or you can simply say Office chat software with full control. If you know any other which you think worth mentioning in this list, please let us know…


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