Zulip is an open‑source, threaded team chat platform that organizes conversations by topics. Looking for free instant‑messaging solutions that can replace or complement Zulip? Below is a curated list of 20 free (or freemium) messaging tools—ranging from open‑source self‑hosted options to popular SaaS services—that support real‑time collaboration for teams of any size.
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Open‑source, self‑hosted Slack‑like workspace with channels, direct messages, and rich integrations.
Fully open‑source chat server offering public and private channels, video calls, and extensive customization.
Web and desktop client for the Matrix protocol; decentralized, end‑to‑end encrypted chat with bridges to other services.
Popular SaaS chat with searchable message history (up to 10k messages), channels, and app integrations.
Free voice, video, and text chat platform with servers, channels, and robust community moderation tools.
Microsoft’s collaboration hub offering chat, file sharing, and limited meeting capabilities at no cost.
Cloud‑based messenger with secret chats, large group support, bots, and cross‑platform clients.
Open‑source, end‑to‑end encrypted messenger focused on privacy; supports one‑to‑one and group chats.
Widely used mobile messenger with group chats, voice/video calls, and end‑to‑end encryption.
Chat platform built for developers, integrating with GitHub/GitLab repositories and offering public rooms.
Secure messaging and file sharing with built‑in encryption and optional team chat features.
Privacy‑first messaging app with encrypted group chats, file sharing, and collaboration tools.
Team messaging with channels, direct messages, and integrated productivity tools; free tier for small teams.
Free tier of Zoho’s chat solution offering channels, bots, and integration with the Zoho suite.
Combines chat, task management, and workflow automation; free plan includes unlimited users and basic features.
Simple team chat with unlimited messages, file sharing, and AI‑powered search in its free plan.
Free group messaging app from Meta, supporting text, images, and polls across iOS, Android, and web.
Open‑source, self‑hosted chat system with channels and real‑time notifications; built on Ruby on Rails.
Free, cross‑platform XMPP server for building custom chat solutions; extensible via plugins.
Web‑based XMPP client that can be embedded in websites; works with any XMPP server (e.g., Openfire, Prosody).