Zulip Team Chat Application

Zulip is a free and open-source team chat application that organizes conversations into topic-based threads, combining real-time chat with threaded discussions. Founded by Tim Abbott and Waseem Daher in 2012 (originally commercial), acquired by Dropbox in 2014 and open-sourced in 2015. Now developed by Kandra Labs (Cambridge, Massachusetts) with 800+ contributors. Key features: topic-based threading: every message belongs to a Stream (channel) and a Topic (thread), enabling multiple conversations simultaneously without confusion. Streams (public, private, web-public) for organizing teams and projects. Topics within streams for focused discussions with persistent history. Personal and group direct messages. Rich text with Markdown: bold, italic, code blocks, lists, tables, quotes, LaTeX math (KaTeX). File and image sharing with inline previews. Message edit history and topic editing. Drafts across multiple conversations. Keyboard shortcuts (Vim-like key bindings). Notifications: email, desktop, mobile push with per-stream and per-topic customization. Custom emoji. Over 100 native integrations (GitHub, GitLab, Jira, Travis CI, Sentry, RSS, Zendesk) via webhooks and bots. Bot framework with Python API. REST API and real-time event API. Authentication: email/password, Google, GitHub, GitLab, Apple, SAML, LDAP/AD. Handles 10,000+ user organizations. Self-hosted (Docker) or cloud-hosted. Apache-2.0.