Zulip is described as 'Threaded group chat with topics for live or async collaboration, open-source, supporting self-hosted or cloud use, suited for organized team discussions' and is a very popular instant messenger in the social & communications category. There are more than 100 alternatives to Zulip for a variety of platforms, including Android, iPhone, Web-based, Windows and iPad apps. The best Zulip alternative is Signal, which is both free and Open Source. Other great apps like Zulip are Telegram, Element, Discord and Matrix.
Open-source chat server supporting real-time group, direct, and private messaging, video calls, file sharing, helpdesk chat, API integrations, desktop notifications, emojis, LDAP authentication, cross-platform apps, and customizable extensions for teams.
Provides a chat experience over email, with all messages and contacts stored on user devices, open source code, group media support, and compatibility with any provider. No central servers, no tracking, works without SIM, and can be used by anyone just via email.
Lightweight communication platform with unlimited channels, seamless voice and video, screen sharing, private file sharing, advanced task and calendar tools, robust privacy features, emoji and thread support, and multi-platform efficiency for gaming or team communities.
Offers secure messaging with end-to-end encryption, unlimited free calls, group chats for up to 250 members, rich media sharing, emoji reactions, AR lenses, self-destruct messages, affordable international calls, community channels, and robust privacy across devices.
Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG].
Encrypted messenger supporting multi-platform access, unlimited group and private chats, file and voice message sharing, decentralized operation, open-source code, custom themes including dark mode, advanced moderation, push notifications, and no advertisements.
Peer-to-peer group chatting over Tor and IPFS, with local-first encrypted messaging and no central servers, offers privacy-focused decentralized collaboration for teams, supporting desktop and mobile. FOSS, open to contributors, and avoids surveillance-based tracking.
A comprehensive collaboration platform within Office 365, providing centralized chat, file sharing, and HD video meetings. Accessible on multiple platforms, it offers enterprise-grade security and compliance, customizable notifications, and private to group chat sessions.
Trillian is an instant messaging app that works on phones, tablets, and desktops while keeping your chats neatly synchronized between all of them! We think conversation should be easily shared between all of your devices, not trapped as text messages on your phone.
Provides comprehensive communication features including group video calls, voice calls, fast messaging, photo sharing, and location mapping. Access through mobile and web platforms with real-time notifications, ensuring seamless interactions using multimedia tools.
Powered by WebRTC, Real-time video call, chat room and screen sharing entirely browser based.
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