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.

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