Mattermost

Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of Defense and Fortune 500s, our platform runs on-premises and in private clouds, delivering secure messaging, file sharing, workflow automation, audio/screenshare, and project management—all with full data and operational control. Mattermost powers high-stakes workflows across mission planning, real-time, real-world operations, DevSecOps, incident response, and cyber defense—enabling secure collaboration from tactical edge and DDIL environments to enterprise HQ. Teams operate across web, desktop, and mobile, with embedded interoperability for Microsoft Teams, Outlook, and Microsoft 365. For AI-enabled organizations, Mattermost offers the Intelligent Mission Environment (IME)—a self-hosted, multi-user, multi-agent framework for AI-accelerated workflows with sovereign and global models. Built on an open core and shaped by 4,000+ contributors, Mattermost is co-developed with leading security experts to meet the world’s most demanding operational needs. Learn more at mattermost.com