Mattermost
Software DevelopmentCalifornia, United States51-200 Employees
Mattermost provides a secure collaboration platform designed for mission-critical operations. It serves national security, government, and critical infrastructure clients—including the U.S. Department of Defense, utilities, banks, and other essential services—supporting out-of-band incident response, DevSecOps workflows, and mission operations. The product portfolio includes enterprise software and single-tenant SaaS options that enable collaboration across web, desktop, and mobile, with channel-based messaging, file sharing, audio calls, and screen sharing, along with integrated tooling, workflow automation, and AI assistance. Based in Palo Alto, California, Mattermost operates as a mid-sized software developer focused on secure collaboration for complex environments. In June 2026, Mattermost announced a collaboration with archTIS, Arqit, and Whitespace Ventures to deliver sovereign, AI-enhanced operational collaboration for Defence.