An open-source messaging app emphasizing privacy with encrypted communication. Share texts, calls, photos, and videos without ads or trackers, available across major platforms. Developed by Signal Technology Foundation and praised globally for security measures.

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.

Go ahead, video chat with the whole team. In fact, invite everyone you know. Jitsi Meet is a fully encrypted, 100% open source video conferencing solution that you can use all day, every day, for free.

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.

Jami (formerly GNU Ring, SFLphone) positions itself as a potential free Skype replacement

Wire is the most secure collaboration platform featuring messenger, voice, video, conference calls, file-sharing, and external collaboration –all protected by the most secure end-to-end-encryption.

Provides video conferencing with high-quality video and screen sharing, supporting up to 100 participants, real-time whiteboard collaboration, group messaging, and VoIP. Compatible across devices including smartphones and PCs, offering flexibility for remote meetings.

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

BigBlueButton enables universities and colleges to deliver a high-quality learning experience to remote students.

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.

Nextcloud Talk is a fully self-hosted audio/video and chat communication service. It features web and mobile apps and is designed to offer the highest degree of security while being easy to use.

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.