Alternative to
Open-source alternatives to Slack: which still ship
6 open-source startups in this directory are positioned against Slack. 5 pushed code in the last 30 days, 0 have been quiet for 31–120 days, 1 has not pushed in over 120 days or is archived. “Alternative to Slack” is a judgment by Jev, TypeSafe’s classifier, made from the repository’s own name, description and homepage, and printed only when it put that match at 0.5 or better. It is not a claim these projects make about themselves, it is not a feature comparison, and Slack has nothing to do with this page.
Ship status
5 of 6 pushed in the last 30 days.
The list
All 6, most-starred first.
The last column is the most recent push to any branch, by a person or a bot — it is not a claim that anyone is maintaining the project, and a quiet repository may be a finished one.
| Project | What it does | Stars | Ship status | Last push |
|---|---|---|---|---|
 Rocket.ChatRocketChat/Rocket.ChatStill shipping | The Secure CommsOS™ for mission-critical operations | 46.2K | Still shipping | |
 mattermostmattermost/mattermostStill shipping | Mattermost is an open source platform for secure collaboration across the entire software development lifecycle.. | 39.3K | Still shipping | |
 zulipzulip/zulipStill shipping | Zulip server and web application. Open-source team chat that helps teams stay productive and focused. | 26K | Still shipping | |
 element-webelement-hq/element-webStill shipping | A glossy Matrix collaboration client for the web. | 13.6K | Still shipping | |
 chattinode/chatStill shipping | Instant messaging platform. Backend in Go. Clients: Swift iOS, Java Android, JS webapp, scriptable command line; chatbots | 13.5K | Still shipping | |
 synapsematrix-org/synapseGone silent | Synapse: Matrix homeserver written in Python/Twisted. | 12.1K | Gone silent |
Related collections
Sideways from here.
The 8 largest other alternatives in the directory, then the other ways to slice it.