Discourse vs Zulip

Comparing two open source alternatives to Discord and Slack . Use the comparison below to decide which one fits your needs.

Discourse

GPL-2.0

A platform for community discussion. Free, open, simple.

Apache-2.0

Open-source team chat with a unique topic-based threading model that makes it easy to follow multiple conversations.

	Discourse	Zulip
License	GPL-2.0	Apache-2.0
Self-hostable	Yes	Yes
GitHub Stars	46,646	24,935
Forks	8,857	9,728
Open Issues	170	2,040
Last Commit	Mar 28, 2026	Mar 27, 2026
First Released	Jan 12, 2013	Sep 25, 2015
Categories	Team Chat & Messaging Tools	Team Chat & Messaging Tools
Tags	#forum #chat	#chat #messaging #collaboration

Simple, open source team messaging platform

The communications platform that puts data protection first.

Mattermost is an open source platform for secure collaboration across the entire software development lifecycle..