Zulip is an open-source team chat alternative to tools like Slack or Teams. 

In Zulip, conversations are organized into streams (think channels in Slack) and streams contain topics, which hold conversations around a specific idea. For example, a team organizing a conference may have a stream called “annual summit,” which is divided into topics like “name tags,” “tuesday night catering,” and “new registration links.” 

According to the project maintainers, being able to see conversations in context makes it easier to stay informed of what’s going on, even if there are lots of messages being sent. 

“With each conversation in its own space, you can coordinate multiple projects, hold a virtual standup, and plan the next team social — all in one place. No more scrolling up and down through dozens of messages to track down all parts of a conversation. No more context-switching again and again as you catch up on your chat messages,” the maintainers wrote on the website

Other key features of Zulip include SAML authentication, LDAP sync, import and export tools, fine-grained permissions, extensive configuration options, hundreds of available integrations, Slack-compatible webhooks, retention policies, and compliance with GDPR. 

Zulip was created in 2012 as a startup, which was acquired in 2014 by Dropbox. In 2015, Dropbox decided to open source the project. Initially the project was being maintained mostly by Tim Abbott, one of the creators of the project, and in April 2016 he formed Kandra Labs to steward the project and sustain its development. 

At the time of this writing, Zulip has had over 1000 contributors to its codebase and has over 19,000 stars on GitHub.