---
title: 'Senior Full Stack Engineer at Mattermost'
canonical: 'https://feeny.ai/job/senior-full-stack-engineer-mattermost-ontario-hhze2xzrs6mw'
type: 'job'
last_seen: '2026-09-05'
---

# Senior Full Stack Engineer at Mattermost

- **Company:** Mattermost
- **Location:** Ontario, Canada / Toronto, Canada
- **Posted:** 2026-08-07
- **Last confirmed live:** 2026-09-05
- **Apply:** https://job-boards.greenhouse.io/mattermost/jobs/5383421008

## Job description

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](http://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 Go backend and React/TypeScript web frontend, building 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

- Architect and build full-stack features optimized for scalability and performance across Go, React, TypeScript, PostgreSQL, and Redis
- Leverage AI coding agents such as Claude Code and Cursor as a core part of your daily workflow while retaining full accountability for correctness, security, and design decisions
- Develop internal tooling and testing infrastructure to speed up the team's delivery, including agentic workflows and skills that make AI tooling more effective for the broader team
- Own testing strategy across frontend and backend code you ship
- Design and consume REST and WebSocket APIs with solid networking fundamentals
- Maintain the security and compliance standards required by our government and enterprise clients
- Contribute to Mattermost's open-source codebase

## What We Are Looking For

Required:

- Strong full-stack development experience in Go and React, or a comparable stack
- 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
- Bias toward shipping and owning complex software end-to-end without close supervision

Nice to Have:

- Experience with distributed systems or high-availability service architecture
- Familiarity with enterprise or regulated-environment security requirements
- Background in defense, intelligence, or critical infrastructure products
- Open-source contributions
- Experience working on distributed or remote-first teams
- Experience building tools, skills, or workflows on top of AI coding agents including MCP servers, agent skills, or CI-integrated agents

How Success Is Measured

- First 90 Days: Shipping full-stack features on the core platform using an AI-forward agentic development workflow and owning testing strategy across the code you ship.

## Why Mattermost

- Mission-driven work: Your contributions directly support the organizations and missions that depend on secure, reliable collaboration including the U.S. Department of War and critical infrastructure operators worldwide
- Remote-first culture: Work from anywhere with a globally distributed, high-trust team built for autonomy and ownership
- AI-forward environment: We actively adopt and build AI-enabled workflows. Agentic development is core craft here, not a novelty
- End-to-end ownership: Ship and own complex software across the full stack with real accountability for what you build
- Open source at the core: Be part of a vibrant developer community shaping the future of secure collaboration

## Compensation

Mattermost takes a market-based approach to pay. Actual compensation may vary based on location, skills, experience, qualifications, and market conditions.

Target Salary Range: CAD $162,591–$195,000

Canada Eligibility & Compliance

Candidates must be legally authorized to work in Canada without current or future sponsorship.

This role may require obtaining and maintaining a government security clearance or equivalent designation (such as Reliability Status or Secret clearance under Canada's Controlled Goods Program), depending on customer engagement. Candidates must meet eligibility requirements to be considered.

Given Mattermost's work with U.S. defense and government customers, some positions may also require compliance with U.S. export control laws, including EAR and ITAR, which can apply to non-U.S. based employees working on covered technical data. For more information, visit the Bureau of Industry and Security and the Directorate of Defense Trade Controls.

Mattermost is an EEO Employer, we are a remote-first, open-source company.

We are continually working to expand our hiring in more countries and regions, ensuring compliance with local laws and regulations, which takes time.

Mattermost values your unique perspective—we welcome all applicants. We encourage individuals from all backgrounds to apply and are committed to assessing candidates based on their skills and qualifications. We do not tolerate discrimination against staff or applicants based on race, religion, national origin, age, disability, pregnancy status, veteran status, or other personal characteristics.

If you require accommodations during the interview process, please let us know—we’re happy to assist.

## About Mattermost

## Company Overview
- **One-liner**: Mattermost provides a secure, open source collaboration platform for mission-critical work in complex environments, serving enterprise, defense, and government organizations.
- **Entity Type**: Private (open core, subscription-based)
- **Headquarters**: Palo Alto, California, USA (and online at [community.mattermost.com](https://community.mattermost.com))
- **Founded**: 2015 (open source project start)
- **Founders**: Not publicly available in provided sources

## Core Business
- **Primary industry/industries**: Secure collaboration, messaging, workflow automation, sovereign AI
- **Target customers**: B2B, Enterprise, Government, Defense, Critical Infrastructure (ICP: organizations with 2,500+ employees and in-house Dev/Sec/Ops talent)
- **Mission or purpose statement**: “To make the world safer and more productive by developing and delivering secure, open source collaboration software.” [handbook.mattermost.com](https://handbook.mattermost.com/company/about-mattermost)

## Products & Services
- **Mattermost Professional**: Open source (MIT license) messaging platform for teams of 10–50 developers and IT professionals. Self-hosted, with core integrations, archiving, search, and extensibility. [handbook.mattermost.com](https://handbook.mattermost.com/company/about-mattermost)
- **Mattermost Enterprise**: Commercial edition with advanced security, compliance, executive reporting, workflow automation, sovereign AI, and support for large-scale deployments. Includes features like classification banners, data spillage prevention, audit trails, attribute-based access controls, and playbook automation. [mattermost.com](https://mattermost.com/)
- **Key capabilities**: Real-time messaging, channels, audio/screenshare, workflow & playbook automation, Kanban boards, task management, integration platform (open API, webhooks, plugins), sovereign AI agents, Microsoft Teams interoperability. [mattermost.com](https://mattermost.com/)

## Market Standing
- **Valuation/Market Cap**: Not disclosed
- **Key Metric**: Annual Revenue not publicly available; Total Funding not publicly available (private company)
- **Notable Investors/Partners**: Not publicly available in provided sources; strong open source community and partner ecosystem (resellers, system integrators, deployment partners)
- **Growth Signals**: Remote-first company with 70% of R&D staff hired from open source community; used by thousands of organizations globally in 16 languages; trusted by governments, allied militaries, and critical infrastructure entities. [handbook.mattermost.com](https://handbook.mattermost.com/company/about-mattermost) | [mattermost.com](https://mattermost.com/)

## Competitive Advantages
- **Open source core**: Transparency, community-driven innovation, and ability to self-host.
- **Self-sovereign deployment**: Supports air-gapped, on-prem, and private cloud environments – critical for defense and intelligence.
- **Security & compliance**: Zero-trust architecture, classification banners, data spillage prevention, burn-on-read, full audit trails, and sovereign AI (no external dependencies).
- **Workflow automation**: Built-in playbooks, Kanban, and AI agents integrated directly into operational channels.
- **Interoperability**: Integration with Microsoft Teams and other mission-critical tools.

## Strategic Focus
- Accelerating mission-critical collaboration for national security, cybersecurity, and critical infrastructure teams.
- Expanding sovereign AI capabilities (LLM connectivity within customer perimeter) and human-machine teaming.
- Deepening workflow automation and playbook-driven incident response.
- Growing partner ecosystem and enterprise adoption in regulated industries.

## Why Work Here
- **Remote-first culture**: Majority of staff work from home; headquarters is on the internet (community.mattermost.com). Not remote-only – courtesy principle guides communication. [handbook.mattermost.com](https://handbook.mattermost.com/company/about-mattermost)
- **Mission impact**: Work deployed in mission-critical environments supporting defense, intelligence, and cyber organizations worldwide. [mattermost.com/careers](https://mattermost.com/careers/)
- **High-trust, fast-moving environment**: Ideas win on merit; employees wear multiple hats and have broad impact. [mattermost.com/careers](https://mattermost.com/careers/)
- **Leadership principles**: Earn trust, be a multi-tool player, high impact, customer obsession, ownership, self awareness.
- **Engineering culture**: ~70% of R&D staff come from open source community; contributors can transition to paid roles. [handbook.mattermost.com](https://handbook.mattermost.com/contributors/join-us)
- **Perks**: Not detailed in provided sources, but remote-first flexibility and open source community involvement are core benefits.

## Sources
1. [handbook.mattermost.com – About Mattermost](https://handbook.mattermost.com/company/about-mattermost)
2. [job-boards.greenhouse.io – Mattermost Jobs](http://job-boards.greenhouse.io/mattermost)
3. [mattermost.com/careers – Careers Page](https://mattermost.com/careers/)
4. [mattermost.com – Main Site](https://mattermost.com/)
5. [handbook.mattermost.com – Join Us](https://handbook.mattermost.com/contributors/join-us)

## Other roles at Mattermost

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