Slack Alternatives

Slack Alternatives

Team Collaboration Apps

First off, I want to mention that most of these tools do two main jobs:

  1. Instant messaging - direct communication between users
  2. Chat room system, in a form that is Slack’s specialty

Salesforce bought Slack in 2020, so it was the trigger for others to “go wild”. The ideal alternative should be open-source and self-hosted if needed.

While there were lots of potential successors at some point, after consolidation, only a few are actually viable:

  • Microsoft Teams is Microsoft’s non-open-source monstrosity which I don’t like at all
  • Discord with 150M users in 2021 (source here)
  • Mattermost
  • aka Element, 50M users in 2021

Among the formerly promising ones, Gitter switched to Matrix side and,
Spectrum Chat was bought by GitHub that is now Microsoft, and turned into an awesome free GitHub module called Discussions.
We also still have Rocket.Chat which used to be one of the best open source Slack alternatives, but I think it’s slowly dropping out of the race, as well as Zulip which I didn’t know is open-source. Što se Zulip-a tiče, baš mi se sviđa Markdown formatting i fast search.

There are many more new entrants as Slack alternatives, but these were the main ones.

We've Tried 7 Free Slack Alternatives (May 2019) Here's Our Feedback


Discord is almost a 1:1 clone of Slack and really looks great, although I think it started out more as a voice VoIP app. Everything about Discord is free but proprietary and not open-source, but still they are very popular. In fact, right now looks like they’re way more popular than Matrix or Mattermost.

All in all, it looks the most like perfect Slack clone.


Mattermost is open-source, self-hostable and I think it’s perfect for teams; they think so too as their slogan is “make your work flow”. I especially like that it has some specificities (Slack + Trello) that makes it the most comprehensive project management offer for small teams.

From a technical perspective, it’s fantastic: the server is written in Go, the mobile app uses React Native, and the web app uses React.

Basically, for such small teams, EVERYTHING is free and without limits: unlimited message search & history, unlimited teams, users, channels, boards, unlimited file storage, unlimited group calls with screenshare, unlimited plugins, apps and integrations.

Since 2021, they have started to move towards Slack and introduced Channels just like in Slack or Discord. At that same time, the biggest change were the Boards segment, a kanban boards with calendars and everything else, which they have called Focalboard and may rightfully think of as a open-source alternative to Trello, Asana and Notion.

Voice calling and screen Sharing in Channels were also introduced only in 2022. I should note that video calling is not supported, only screen sharing and voice calls, but recording is still completely free. Although there is no video calling, that can be easily done with an Whereby integration, for example.

Great selection of various integrations, and I in particular noticed 42wim/matterbridge, quite a while ago.


Gitter is similar to Slack’s chat-room system, but it’s open-source and I like that it supports GitHub-flavored Markdown in chat messages. It’s quite popular too, and that’s totally its main idea - developing and growing communities, which is why many developers use it. There are a couple of reasons it’s so popular:

  • it’s totally free, with unlimited people, unlimited message history and unlimited number of integrations
  • complete conversation history is public and indexed by search engines, and every message is shareable with a permalink

Speaking of its further development, there are potential issues here. Back in 2017, GitLab bought it, and then, at the end of 2020, Matrix’s parent company bought it from GitLab and announced that it would slowly completely integrate it into Matrix’s Element client. Latest announcement was that Gitter is going fully native Matrix in Feb. 2023.

Matrix is an all-in-one open-source platform for communication, so it enables development of not just Slack clones but also Telegram clones. Of all its competition, it’s by far the most open and with the most varied options.

Not just is Gitter slowly being integrated into this platform after the acquisition, but in mid-2022, one of its major competitors, Rocket.Chat announced it would be transitioning to Matrix protocol for communication, becoming one amongst Matrix clients.

It’s also important to note that WordPress Project is likely to switch over to Matrix for its community as well, from Slack.

Clients: An Impressive Number Doesn’t Guarantee Quality

The selection of clients is impressive, counting in the dozens. Though that sounds great, not all of them are actually good, as competition doesn’t guarantee quality. I’ll be testing the ones frequently touted as best-in-class.

Web Client: Element, Hydrogen or Cinny, Desktop: Element but I’m not happy with the choice, Mobile: Element

Element the main, fully-featured Matrix client, for all platforms: desktop (scoop install element), mobile and Web. The reason I’m avoiding the desktop version is that it is an Electron Wrapper app, while I normally use the Web and mobile versions.

Hydrogen, vector-im/hydrogen-web, is a lightweight Web client, accessible at: Obviously, the same company behind Element is hosting it, but it really is fast and light, and I really like it for the Web.

Cinny is Web-focused, and may even be better than Electron. Though there’s a desktop client scoop install cinny, it’s merely an Electron wrapper, so I didn’t even try it.

Nheko is a native desktop client, setup with scoop install nheko. Considering it’s written in C++/Qt, I’m surprised at its size of 110M. The rendering of UI elements was really poor and clunky for me, so I uninstalled it right away.

NeoChat is part of KDE, also written in C++/QML, so I’m not interested in even trying it since it’s likely to have the same issues as Nheko.

Fractal is part of GNOME, and written in Rust. But, the website and screenshots weren’t promising and it isn’t available from scoop, so I’ll skip it.

FluffyChat is a cute client for Web and mobile, but sorry, not for desktop. After testing it, I think Element is the better choice across both platforms.

Bridges for Interoperability

Bridges are used for “puppeting”, meaning they allow messages to appear as if they were sent from the normal sender to other users.

There are bridges for many platforms, such as:

  • I’ll probably use the WhatsApp bridge, since the client for WhatsApp on desktop is dismal,
  • The Telegram bridge so I can communicate perfectly through Telegram
  • and there’s even a Signal bridge

They’re all self-hosted, but many of them are hosted for free, for instance on

New Ones Keep Popping Up

I don’t know why, but new ones keep appearing on the market all the time.

  • Linen, for example, has recently arrived - it looks like Gitter to me, but whatever. Its slogan is “Google-Searchable and community focused Slack alternative” and since everyone is targeting Gitter-market, maybe it’s worth supporting this.

Iskreno mi se Linen baš sviđa pošto može even access your Slack history beyond 90 days without upgrading Slack.


Channel Webhook


Prebacivanje nekog Slack webhook-a u neki drugi format se zove “Webhook Relay”

You don’t really need this… Discord already converts Slack on their end. Just add /slack to the URL ie.

Zašto Discort? Zato što je client 100 puta brži nego Slack. Sve podatke možeš da prebaciš: pR0Ps/slack-to-discord: Import a Slack export into a Discord server

Možeš sa RSS na Slack (i Discort) schu/feedcruncher: RSS to Slack/Discord webhook

Kako podesiti na foru Discort server?

Discohook Sve što podesiš, samo kroz jedan Webhook. The easiest way to personalise your Discord server.

date 28. Aug 2019 | modified 29. Dec 2023
filename: Self-Hosting » Research » Team Communication aka Slack Clones