Zulip

Zulip is an organized team chat platform for distributed teams. Its stream-and-topic structure keeps discussions grouped by subject, making it easier to follow parallel workstreams and revisit decisions. Organizations can choose Zulip Cloud or self-host the open-source software, and use its desktop and mobile apps, integrations, and API. Zulip serves business, education, research, events, open-source projects, and communities.