Slack Alternatives for Linux

Discord is a versatile free communication platform designed initially for gamers but now widely used for communities of all types. It offers voice and text chat, video calls, and robust server customization for groups of any size, providing a centralized hub for real-time interaction and community building.

Jitsi is a free and open-source suite of secure, flexible communication tools. It offers multi-platform support for voice (VoIP), video conferencing, and instant messaging, emphasizing privacy and ease of use with no account required to start a meeting.

Mattermost is an open-source, self-hosted platform for secure team collaboration, offering a Slack-alternative with emphasis on data control, privacy, and customizability. It provides a range of communication and project management tools for distributed and technical teams.

Wire is a secure, cross-platform messaging and collaboration client offering end-to-end encryption by default for all communication types including messaging, voice and video calls, and file sharing across desktop and mobile devices.

Ora is a comprehensive, real-time project management platform designed for teams of all sizes. It offers a flexible and intuitive interface, enabling teams to manage tasks, track time, collaborate effectively, and streamline workflows within a single workspace. From agile methodologies to traditional project planning, Ora provides the tools necessary to enhance productivity and achieve project goals.

Rocket.Chat is a comprehensive free and open-source team communication platform, offering real-time chat, audio/video conferencing, screen sharing, and file sharing. Designed for flexibility, it can be self-hosted on-premises for maximum control and customization, making it ideal for organizations prioritizing data privacy and security.

eXo Platform is an open-source enterprise social collaboration platform designed to connect employees, share knowledge, and improve communication and productivity within organizations. It offers a comprehensive suite of tools including social networking, document management, project management, and real-time communication features.

AirSend is a comprehensive communication and collaboration platform designed for teams, offering integrated messaging, file sharing, and task management. It centralizes digital workspaces, enabling seamless interaction, efficient file organization, and enhanced productivity for businesses of all sizes. With features like unlimited storage and robust security, AirSend aims to streamline team operations.

Matrix is an open network for secure, decentralized real-time communication. It provides a flexible protocol for developers to build collaborative applications like instant messaging, VoIP, and video conferencing, enabling seamless communication across different service providers.

Twist is a unique team communication tool designed to foster focused, organized, and asynchronous collaboration, minimizing real-time distractions. It provides threaded conversations, topic-based channels, and a clear inbox to help teams stay productive without the chaos of constant notifications, promoting thoughtful discussions over instant replies.

Zulip is a powerful open-source group chat application designed for team collaboration. It uniquely structures conversations around topics, enabling users to easily catch up on important discussions and manage information overload. Zulip facilitates secure communication with integrated file sharing and various integrations.

Dialog Messenger is a robust, feature-rich enterprise messaging solution designed for businesses prioritizing security, privacy, and control. Available for both private server deployment and cloud hosting, it facilitates secure text, voice, and video communication across multiple devices, enabling seamless collaboration and real-time interaction within organizations.

Gitter is a free and open-source instant messaging and chat service designed specifically for developers and users of GitHub projects. It provides real-time communication within the context of software development teams and communities.

Wickr is a secure and private instant messaging platform designed for individuals and teams who prioritize confidentiality. It offers end-to-end encryption, self-destructing messages, and a focus on anonymity to ensure that conversations and shared data remain protected.