6 open-source alternatives to Slack
These tools replicate the core functionality of Slack without the SaaS subscription. Most are self-hostable; some also offer managed cloud editions.
Why switch? Self-hosting eliminates per-seat fees and keeps data on your infrastructure. Trade-offs: ops overhead, slower feature shipping, and you own backups. Pick a managed-cloud edition if you want fewer headaches.
Element
element.io
Open source
Fully-featured Matrix client for Web, iOS & Android.
Communication - Custom Communication SystemsFree
Mattermost
mattermost.com
Open sourceTop 10K
Open-source alternative to Slack.
Slack alternativesFree
RelatedChat
relatedcode.com
Open source
Open-source alternative to Slack.
Slack alternativesFree
Rocket.Chat
rocket.chat
Open source
Communications platform that puts data protection first (alternative to Gitter.im and Slack).
Communication - Custom Communication SystemsFree
Spacebar
spacebar.chat
Open source
Open-source alternative to Slack.
Slack alternativesFree
Zulip
zulip.org
Open source
Zulip is a powerful, open source group chat application.
Communication - Custom Communication SystemsFree