Mattermost

We’re helping the world build better software by aligning teams, tools, and processes at each stage of the development lifecycle. Our customers use Mattermost to increase their productivity, build and execute scalable workflows, and collaborate outside of code — all while contributing to a shared, flexible, and extensible platform built just for them.

We’re committed to open source and our community of over 4,000 contributors worldwide. At Mattermost, you get to build open source software benefiting thousands of companies, institutions, schools, and nonprofits around the globe.

01 Oct, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com Mattermost  is seeking an experienced and visionary  Lead Site Reliability Engineer (SRE)  to guide the architecture, reliability, and operational excellence of the infrastructure powering our...
01 Oct, 2026
Mattermost Toronto, Ontario, Canada
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a Staff Full Stack Engineer to set the technical direction for and scale Mattermost’s core web platform for teams operating in defense and critical infrastructure sectors. You’ll...
01 Oct, 2026
Mattermost Ontario, Canada; Toronto, Ontario, Canada
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a  Senior Full Stack Engineer to help build and scale Mattermost's core web platform for teams operating in defense and critical infrastructure sectors. You will contribute across our...
01 Oct, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a Staff Full Stack Engineer to set the technical direction for and scale Mattermost’s core web platform for teams operating in defense and critical infrastructure sectors. You’ll drive...
01 Oct, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a  Senior Mobile Engineer to take ownership of the Mattermost mobile experience for teams working in defense, intelligence, and critical infrastructure. Our users operate in DDIL...
01 Oct, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a Senior Full Stack Engineer to help build and scale Mattermost's core web platform for teams operating in defense and critical infrastructure sectors. You will contribute across our...
10 Sep, 2026
Mattermost Ontario, Canada; Toronto, Ontario, Canada
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a  Senior Full Stack Engineer to help build and scale Mattermost's core web platform for teams operating in defense and critical infrastructure sectors. You will contribute across our...
10 Sep, 2026
Mattermost Toronto, Ontario, Canada
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a Staff Full Stack Engineer to set the technical direction for and scale Mattermost’s core web platform for teams operating in defense and critical infrastructure sectors. You’ll...
10 Sep, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a Staff Full Stack Engineer to set the technical direction for and scale Mattermost’s core web platform for teams operating in defense and critical infrastructure sectors. You’ll drive...
10 Sep, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com We are seeking a Senior Full Stack Engineer to help build and scale Mattermost's core web platform for teams operating in defense and critical infrastructure sectors. You will contribute across our...
10 Sep, 2026
Mattermost United States
Mattermost is the leading collaborative workflow platform for defense, intelligence, security, and critical infrastructure. Trusted by the U.S. Department of War 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. To learn more, visit  www.mattermost.com Mattermost  is seeking an experienced and visionary  Lead Site Reliability Engineer (SRE)  to guide the architecture, reliability, and operational excellence of the infrastructure powering our...