Alternatives to: Slack

Abilian SBE is an open source enterprise social network that improves communication, collaboration, and knowledge management to boost productivity.

eXo Digital Workplace is a collaborative platform that streamlines teamwork, communication, and document management.

Fleep is a secure and user-friendly business messenger designed to simplify team communication and collaboration.

ginlo Business is a secure and efficient communication platform for organizations, offering enhanced security and compliance features.

HumHub is a flexible, open-source social intranet platform for seamless communication and collaboration within organizations.

Infomaniak kChat is a secure, AI-powered instant messaging platform for businesses, designed for enhanced collaboration and data privacy.

IPBRICK provides a secure, private cloud-based communication and collaboration platform designed to digitally transform businesses.

Jamespot is a modular, customizable, and secure cloud-based platform that enhances team collaboration and communication.

Mattermost is a secure and adaptable collaboration platform designed for mission-critical work in highly regulated environments.

Netframe is a secure, open-source, and customizable digital workplace solution that simplifies team collaboration and communication.

Nextcloud Social is a collaborative app that adds social networking features to Nextcloud, fostering communication and engagement among users.

Nuclino is a fast, simple, and modern collaboration platform that brings knowledge, documents, and projects together in one place.

OpenTouch Message Center (OTMC) was a unified messaging application providing voicemail, fax, and email management, but is now discontinued.

Rainbow by Alcatel-Lucent Enterprise is a secure, all-in-one cloud communication and collaboration platform enhancing team collaboration and employee productivity.

Rainbow by Alcatel-Lucent Enterprise is a secure, all-in-one cloud communication and collaboration platform that enhances team collaboration and employee productivity.

Rocket.Chat is a secure, collaborative communication platform that enables real-time communication and streamlined workflows for teams and organizations.

Stackfield is a secure task and project management platform for organizations with sensitive data, offering end-to-end encryption and a comprehensive suite of collaboration tools.

Stackspin is an open-source platform providing a secure and easy-to-manage suite of collaborative apps for value-driven teams.

Threema Work is a secure and compliant business messenger that enhances team communication and boosts productivity while ensuring data privacy and compliance with regulations.

Threema Education offers a secure, private, and affordable instant messaging solution for schools and universities, facilitating efficient communication while protecting student and teacher data.

Threema OnPrem is a self-hosted, highly secure enterprise messaging solution providing total data ownership and control.

Tracim is an open-source, all-in-one collaborative platform designed to streamline team communication, project management, and knowledge sharing.

W'Sweet is a modular, open-source collaborative suite offering secure communication, file sharing, and video conferencing for organizations of all sizes.

Whaller is a secure and customizable collaboration platform designed for efficient communication and document management within organizations of any size.

Wire is a secure collaboration platform providing end-to-end encrypted communication and file sharing for individuals, businesses, and governments.