Mattermost

The platform provides a self‑hosted collaboration environment that includes chat channels, workflow automation, voice calling, screen sharing, and AI integration. It runs as a single Linux binary written in Go and React, stores data in PostgreSQL, and is released under an MIT license on a monthly schedule. Users can deploy it on‑premises via Docker, Ubuntu, tar archives, Kubernetes, or other supported methods, and native clients are available for Android, iOS, Windows, macOS, and Linux.

It targets software development teams and other mission‑critical groups that need secure, extensible communication integrated with tools such as GitLab, as well as use cases like DevSecOps, incident resolution, and IT service desks. The system offers APIs, webhooks, slash commands, apps, and plugins for custom integrations, and includes features for playbook automation, project and task management, and real‑time collaboration.

What distinguishes it is the focus on operational sovereignty and security for environments such as national‑security, critical‑infrastructure, and air‑gapped deployments. The platform is designed to be adaptable, allowing organizations to control data residency, extend functionality, and integrate with existing workflows while maintaining compliance and resilience.