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.

Pidgin is a chat program which lets you log into accounts on multiple chat networks simultaneously. This means that you can be chatting with friends on XMPP and sitting in an IRC channel at the same time.

Exchange messages without SMS fees using this app for iPhone, Android and desktop, featuring group chats, multimedia sharing, and video calls. The app requires an internet connection and the latest version for optimal functionality.

Offers unified communication for teams with advanced real-time messaging, contextual features, versatile chat tools, and organized conversations in dedicated channels with integrated file sharing on Mac, Windows, Linux, and mobile platforms for enhanced productivity.

Mattermost is a secure, open source platform for communication, collaboration, and workflow orchestration across tools and teams.

Zulip is the only modern team chat app that is designed for both live and asynchronous conversations. Zulip topics create a separate space for each discussion, so different conversations will never get in each other's way.

Rocket.Chat is a Web Chat Server, developed in JavaScript, using the Meteor fullstack framework.

Embrace lag-free, secure voice chats with TeamSpeak, offering cross-platform compatibility and low CPU usage. Enjoy advanced audio controls, push-to-talk, in-game overlay, and security-focused privacy features, tailored for gamers seeking seamless communication.

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.

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.

Ripcord is a desktop chat client for group-centric services like Slack and Discord. It provides a traditional compact desktop interface designed for power users. It's not built on top of web browser technology: it responds quickly to input, sips gently from computer...

ChatSecure is a free and open source messaging app that features OTR encryption over XMPP. You can connect to your existing accounts on Facebook or Google, create new accounts on public XMPP servers(including via Tor), or even connect to your own server for extra security.