Senior Full Stack Engineer - Mattermost

About Mattermost

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 delivers secure messaging, file sharing, workflow automation, and project management with full data and operational control.

The Role

We are seeking a Senior Full Stack Engineer to help build and scale our core web platform. You will contribute across our Go backend and React/TypeScript frontend, building features that meet strict security, compliance, and reliability requirements. Our engineering culture is AI-forward; we expect engineers to work fluently with AI coding agents (e.g., Claude Code, Cursor) as a core part of their daily craft.

What You Will Do

• Architect and build full-stack features optimized for performance using Go, React, TypeScript, PostgreSQL, and Redis.
• Leverage AI coding agents for scaffolding, refactoring, and testing while maintaining full accountability for code quality and security.
• Develop internal tooling and agentic workflows to accelerate team delivery.
• Own the testing strategy across the frontend and backend code you ship.
• Design and consume REST and WebSocket APIs with solid networking fundamentals.
• Maintain security and compliance standards required by government and enterprise clients.

What We Are Looking For

• Strong full-stack development experience in Go and React (or comparable stacks).
• Proficiency in designing/consuming REST and WebSocket APIs.
• Experience with relational databases (PostgreSQL), schema design, and query optimization.
• Hands-on daily fluency with AI coding agents (Claude Code, Cursor, Copilot).
• A bias toward shipping and owning complex software end-to-end.

Why Mattermost

• Mission-Driven: Support organizations that depend on secure, reliable collaboration.
• Remote-First: Work from anywhere with a high-trust, distributed team.
• AI-Forward: Agentic development is core to our engineering culture.
• Open Source: Contribute to a vibrant developer community.

Eligibility & Compliance

• Candidates must be legally authorized to work in Canada without sponsorship.
• This role may require obtaining and maintaining a government security clearance (e.g., Reliability Status or Secret clearance under Canada's Controlled Goods Program).