Mattermost

Mattermost is an open core, self-hosted collaboration platform for secure team communication across the software development lifecycle. This card describes the open source self-hosted server; a hosted cloud option also exists for teams that want to try it without running their own instance.

It provides chat, workflow automation, voice calling, screen sharing, and AI integration. The server is written in Go and React, runs as a single Linux binary, and uses PostgreSQL. Mattermost also supports APIs, webhooks, slash commands, apps, and plugins, with clients for web, Android, iOS, Windows, macOS, and Linux.

The core server ships a compiled build under an MIT license every month. Self-hosted installs cover Docker, Ubuntu, tar, Kubernetes, Helm, Debian, and RHEL, so teams can deploy on the platform that fits their infrastructure. Over 700 integrations extend it through the Mattermost marketplace.