Self-hosted alternatives
Open source alternatives to Slack
Slack is a hosted team chat product with channels, threads, and app integrations.
Original introduction
A chat tool holds a company's day-to-day memory, and Slack, the hosted chat product from Salesforce, keeps that memory on its own service. Running chat yourself keeps that history on your own server. All five projects listed here carry an OSI licence and were updated within the last year. The bigger choice is model: two are open core with paid tiers on top, while others are fully community licensed.
Published by Salesforce. The projects below are sorted by GitHub stars. Star counts and last commit dates are read from the public GitHub API. The line under each name is generated from the category, the licence, and whether the project can be self-hosted. Fetched . 5 of 5 have an OSI-approved SPDX licence, a commit in the last 12 months, and a repository GitHub has not archived.
1Rocket.Chat
RocketChat/Rocket.Chat
Team chat. Licence: MIT. Self-hosted: yes.
- Licence
- MITOpen core
- GitHub stars
- 46,274
- Last commit
Counts as open source: OSI-approved licence, commit within 12 months, and the repository is not archived.
Repository on GitHubProject site
Also listed as an alternative to Microsoft Teams.
2Mattermost
mattermost/mattermost
Team chat. Licence: AGPL-3.0-only. Self-hosted: yes.
- Licence
- AGPL-3.0-onlyOpen core
- GitHub stars
- 39,333
- Last commit
Counts as open source: OSI-approved licence, commit within 12 months, and the repository is not archived.
Repository on GitHubProject site
Also listed as an alternative to Microsoft Teams.
3Zulip server
zulip/zulip
Team chat. Licence: Apache-2.0. Self-hosted: yes.
- Licence
- Apache-2.0
- GitHub stars
- 26,050
- Last commit
Counts as open source: OSI-approved licence, commit within 12 months, and the repository is not archived.
4Element Web
element-hq/element-web
Team chat. Licence: AGPL-3.0. Self-hosted: yes.
- Licence
- AGPL-3.0
- GitHub stars
- 13,575
- Last commit
Counts as open source: OSI-approved licence, commit within 12 months, and the repository is not archived.
Repository on GitHubProject site
Also listed as an alternative to Microsoft Teams.
5Stoat
stoatchat/for-web
Team chat. Licence: AGPL-3.0. Self-hosted: yes.
- Licence
- AGPL-3.0
- GitHub stars
- 767
- Last commit
Counts as open source: OSI-approved licence, commit within 12 months, and the repository is not archived.