Posts Tagged: team chat

Top open source alternatives to Slack team chat

There are a lot of open source alternatives when it comes to team chat software.

As it is with every team collaborative environment, communication is very important. What software works best in your case depends on your requirements and preferences.
The first collaboration tool that comes in mind is the indispensable team chat. It does not matter if your work colleagues are sitting across the room from you or on the other side of the planet. Communication in real-time makes conversations faster, easier, reducing confusion and misunderstandings.
While some circles still think that chat applications van be distraction. And they sure can be one if not contained. But I believe that if you are committed to your work, you can come to agreement to reel of-topic chats. Creating “general” channels can help loosen up, leading to better work flow. But it is equally important to be able to give yourself the space to work uninterrupted. While writing this article I have three team collaboration tools running in background. Still I keep all my notifications silenced and I check them only when the breaks in my work allow for it.
I recommend using an open source tool that is made exclusively for work. I like to separate work from personal communications and that is the main reason for me to try the software listed bellow.


Slack is the corner stone when it comes to collaborative chat software. It is preferred by the software development companies and for a good reason. It is stable, well designed and with all the right options. But Slack is not open source not to mention that it is pay to use. As such it is not very flexible. As a simple example is that you cant self host it. For big companies with lots of sensitive data this is a major turn off.
Open source with its access to the code helps you ensure that all communications stay private. Of course I should mention the option to add or remove features to further improve your work flow.
Let’s check five open source Slack alternatives. From the classics to brand new applications, for your team’s communication needs.


An honorable mention. The truth is that it has no place in any modern company. IRC has been around for a while – about 30 years actually, and it has tons of open source implementations.
As always with the age, come the drawbacks. It lacks features that are must for every modern chat. Security and Identity management barely exist (they are implemented with bot services).
On the good side, IRC is universal. Both servers and clients are available for every platform you can think of. The interface while not something to brag about is intuitive and fast. And if you have been developing open source, you most probably already installed or used IRC.

Let’s Chat

Let’s Chat has a more modern approach to team chat. Its program (also called Let’s Chat) is with MIT license and written on top of the popular Node.js platform. You will find many of the things that are expected of chat client like Slack. Image embeds @mentions, logging and file management. With Let’s Chat you can create chat rooms for every team, or project. It can integrate with your existing authentication servers. This way you can use the same login across all your software in your organization. As an addition Let’s Chat has a nice API that allows it to connect with other tools too.
The program is easy to install and self hosting is not a problem too. You can do it by Vagrant or Docker, or as part of There is an online demo, that does not implement all the features of the project. You can still get the general Idea of the program.


Mattermost is another app with modern approach. It is advertised as private cloud Slack alternative. It is written in Golang with a bunch of JavaScript under the hood of React framework. It supports both public and private chats as well as one on one conversations. It saves archives and is very similar to Slack interface wise. You can find all the expected team chat features. For people switching from Slack there is an import function that will import channels and chat archives.
Sadly as of late only the Team Edition is open source and free.


Rocket chat is my personal favorite. While it can be buggy at times if you are not using the Rocket chat+ client it is a descent program.
Rocket.Chat is written in CoffeeScript and JavaScript on top of Meteor framework. It is available under MIT license. Like most others it is with descent interface and available for both desktop and mobile. It is feature rich with the only thing that I am missing is the “talk to self” option.
Installation is easy and everything is well documented. The server can be on-premise or cloud based on their servers (paid option). As with most programs now days its available on every viable platform. There is an online demo that you can check.
Rocket.Chat features an online demo, and you can check out its source code on GitHub as well. Rocket.Chat is available under an MIT license. was one of the less popular chats but things have changed fast. It rightfully sits among the top alternatives of Slack now. Riot has quite a bit of mobile and web tools that connect to Matrix network. Matrix is open network for secure and decentralized communication. Among the functions I should mention its VOIP implementation. Bridge integrations with Slack, Gitter and IRC are available, for easy replacement with the open source client.
It is the easiest tool to try since it is web based (both client and host). Riot is licensed under Apache 2.0 license.

Other options

This is my personal favorites list and it is far from exhaustive. I encourage you to try and find a few others before you decide what chat to use.
Don’t take everything written in this list for granted. Lately more and more open source software companies are turning the back on free software. Some time has passed since I used some of the tools above and can I give no guarantee that they are still free or open source.