Staff Full Stack 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 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 architecture and technical strategy across our Go backend and React/TypeScript web frontend — partnering across teams to ship features that hold up under strict security, compliance, and reliability requirements . Our engineering culture is AI-forward. We expect engineers to work fluently with AI coding agents such as Claude Code day-to-day — for scaffolding, refactors, code review, and test generation — and treat that as core craft rather than a shortcut. We would rather hire smart people who get stuff done than chase an exact tech-stack match. If you have a track record of shipping and owning complex software end-to-end, we want to hear from you. What You Will Do • Define and drive the technical architecture and roadmap for Mattermost’s core web platform across multiple engineering teams, spanning Go, React, TypeScript, PostgreSQL, and Redis • Set org-wide standards and best practices for AI-agentic engineering workflows — going beyond personal fluency with tools like Claude Code and Cursor to shape how the broader engineering org adopts them, while retaining accountability for correctness, security, and design decisions • Lead the internal tooling and testing infrastructure strategy that speeds up delivery for the broader engineering org, not just your immediate team • Own the testing strategy and quality bar across frontend and backend systems, and hold other engineers accountable to it through design reviews and mentorship • Drive architectural decisions for REST and WebSocket API design, grounded in deep networking fundamentals • Partner directly with security, compliance, and product leadership on strategic technical bets tied to our government and enterprise customer requirements • Mentor senior engineers and act as a technical multiplier across the org • Contribute to and help shape technical direction for Mattermost’s open-source codebase What We Are Looking For Required: • Senior full-stack development experience in Go and React (or a comparable stack), with a track record of owning complex systems end-to-end • Proven experience designing and owning distributed systems or high-availability service architecture at scale • Experience designing and consuming REST and WebSocket APIs with solid networking fundamentals • Relational database experience including PostgreSQL, schema design, and query optimization • Hands-on daily fluency directing AI coding agents such as Claude Code, Cursor, or Copilot for scaffolding, refactors, code review, and test generation — with the judgment to know when to trust the output and when to take the wheel yourself • Demonstrated ability to influence technical direction across multiple teams without relying on formal authority • Experience mentoring senior engineers and raising the technical bar for a broa