Lead Site Reliability Engineer

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 secure, mission-critical collaboration platform. In this role, you will provide technical leadership across our SRE function, driving strategic initiatives for scalability, observability, performance, and automation across cloud and hybrid environments. You will mentor engineers, establish best practices, and collaborate closely with development, security, and operations teams to ensure our customers in defense, government, and critical infrastructure sectors experience exceptional reliability and performance. Responsibilities Include: Define the strategy, architecture, and roadmap for Mattermost’s site reliability engineering function, aligning infrastructure initiatives with product and business goals. Lead the design, deployment, and optimization of production-grade containerized workloads, infrastructure-as-code, and compliant cloud environments for regulated domains (e.g., FedRAMP, DoD). Establish and evolve observability, monitoring, and alerting frameworks to ensure performance, reliability, and capacity planning at scale. Drive incident management processes, including on-call rotations, root cause analysis, and systemic reliability improvements. Partner with security and compliance teams to meet data sovereignty, security, and regulatory requirements. Champion automation and operational excellence to improve efficiency, reduce risk, and scale operations. Oversee cloud cost management and capacity planning to optimize infrastructure spending while meeting performance targets. Build and maintain a developer platform that enables fast, secure software delivery and improves application stability in production. Mentor and coach SRE team members, fostering a culture of learning, collaboration, and technical excellence. Requirements: BS in Computer Science, Cybersecurity, Software Engineering, or a related technical field, or equivalent experience, with 5+ years of relevant experience in site reliability engineering, DevOps, or cloud infrastructure roles. Proven expertise in container orchestration platforms, ideally Kubernetes. Extensive experience with infrastructure-as-code, ideally Terraform. Strong background in cloud platforms, ideally AWS. Demonstrated experience designing and implementing monitoring, alerting, and performance optimization strategies. Exceptional troubleshooting and incident management skills for distributed systems. Proficiency in at least one scripting or programming language for automation. Excellent communication skills with a track record of influencing cross-functional teams. Experience leading globally distributed teams in a remote-first environment. Preferences: Familiarity with observability stacks such as Grafana and Prometheus. Experience designing high-availability, disaster recovery, and scaling architectures. Exposure to GCP and Azure cloud environments. Leadership experience in highly regulated industries such as defense, finance, or critical infrastructure. Experience with U.S. federal compliance frameworks and authorization proc