Chat App Comparison Table

There’s a lot of Slack alternatives out there. I made a table of what I think the major features are. It’s tough to compare the apps like this — there’s a lot of cases where they’re similar on paper, but differ in practice, like with threading.

Open-source
Metadata is kept private
Single sign-on via Keycloak
Message threading
Federation
End-to-end encryption
Easy moderation
Notifications
Multilingual
Message retention
Connection limitations
Integrations
Onmichannel or helpdesk features
Ease of installation and maintence
Can build mobile, desktop, and server apps from source
Slack
No
No
Yes (Paid only)
Yes
Yes (Paid only)
No
Yes (Paid only)
Yes
Yes
Capped at 10k
Yes (on Free plan)
Yes, many
No
Very Easy
N/A
Discord
No
No
No
Yes (messages erased after 24 hours or up to 1 week with paid Boosts)
No
No
Yes
Yes
Yes
Unlimited
None
Yes, many
No
Very Easy
N/A
Matrix
Completely*
No (has replies; threading planned for future release)
Yes
Yes
No (external CLI tools required)
Yes (Unlimited)
Yes
Unlimited
No
Yes, some
No
Difficult
Yes
Rocket Chat
Partially (Pro/EE)
In theory yes, difficult to impossible in practice
Yes (very new)
Sort of (in alpha, not ready for production use)
Yes (beta)
Yes, built-in role editor
Capped at 10k per server, requires Cloud conneciton
Yes
Unlimited
No
Some
Yes
Somewhat difficult
No (docs missing)
Mattermost
Partially (TE/EE)
Yes (beta)
No
No
Somewhat (TE) Yes (EE)
Yes (Unlimited, can also self-host)
Yes
Unlimited
No
Yes, a few
No
Somewhat difficult
Yes
Zulip
Almost completely (HA clustering is paid)
Yes
Yes
Yes (Unique, deep threading)
No
No
Yes
Unlimited
No
Yes, a few
No
Somewhat difficult
Yes