Mattermost

Mattermost is an open source platform for team communication, supporting messaging, commenting/notes, and assignment management. Progress tracking, project planning, resource management, and task management require integrations. It integrates with third-party apps and offers time tracking add-ons. Mattermost gives teams a self-hosted, secure environment, ensuring data control while enabling transparent, real-time collaboration. It suits organizations needing privacy and compliance in their communication workflows.