The best open source Instant Messenger alternative to Rocket.Chat is Element. It's not free, so if you're looking for a free alternative, you could try Element or Matrix. If that doesn't suit you, our users have ranked more than 100 alternatives to Rocket.Chat and many of them are open source Instant Messengers so hopefully you can find a suitable replacement. Other interesting open source Instant Messenger alternatives to Rocket.Chat are Zulip, Element X, Mirotalk and nheko.
Provides secure collaboration with end-to-end encryption, supporting chat, voice, and video calls. Available on all major platforms, it enables digital sovereignty with a decentralized design and interoperability through bridges to systems like Slack and Teams. Includes enterprise-grade SaaS.
Open standard protocol enabling decentralized, encrypted instant messaging, VoIP signaling, IoT device connectivity, and persistent data management across federated servers without central control or single points of failure, bridging communication platforms.
Open-source video conferencing platform with encryption by default, up to 75 participants, live group chat, HD audio, screen and document sharing, Etherpad editing, mobile and browser support, custom deployment options, privacy-first features, and community-driven development.
Threaded group conversations combine live and asynchronous messaging, separating topics for organized collaboration, supporting open-source, cloud, and self-hosted deployments, secure communication with encryption, and multi-platform access for diverse teams.
It is the brand new, and fastest ever, Matrix client. It is for personal and community use, and will support enterprise functionality later this year.
Powered by WebRTC, Real-time video call, chat room and screen sharing entirely browser based.
Matrix-focused desktop chat client supporting secure end-to-end encrypted messaging, voice and video calling, file sharing, emoji, room and community management, multi-theme interface, presence/status, notifications, profiles, and plugin integration for Unix.
Open-source chat platform providing community-focused group messaging, video calls, profile customization with animated avatars, custom emojis, tags, post creation, discovery of communities, and full source code access on GitHub. Entirely donation-funded.
![Profile Interface [PC - 2025]](https://img.alternativeto.net/s/618x394/avif/nerimity_993222_full.png)
![Messages View [PC - 2025]](https://img.alternativeto.net/s/618x394/avif/nerimity_281418_full.png)
![Server Discovery [PC - 2025]](https://img.alternativeto.net/s/618x394/avif/nerimity_282508_full.png)
![Server Settings [PC - 2025]](https://img.alternativeto.net/s/618x394/avif/nerimity_628028_full.png)
An ad-free, theme-able, chatting platform built for privacy and security while offering a huge feature set including bot support, moderation, voice calls, screen sharing, video, embeds and many other features, it's built to be reliable and self-hosted while still allowing...
0xchat is a secure chat app built on the Nostr protocol. It prioritizes security, featuring private key login, encrypted private chats and contacts, encrypted group chats.
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Yes its their main competitor, except for the omnichannel feature