At Mattermost, we build the #1 collaborative workflow solution for defense, intelligence, security, and critical infrastructure organizations. Trusted by governments, financial institutions, and technology companies, our platform enables secure, efficient operations for the world’s most critical teams.

We’re dedicated to empowering organizations to operate with confidence, reducing risks, and accelerating productivity. Guided by our core values of Customer Obsession, Earn Trust, Self Awareness, Ownership and High Impact, we collaborate closely with our customers to deliver solutions that meet complex needs and drive success.

What you’ll be doing

Mattermost is seeking a Senior React Native Engineer to join our mobile engineering team and build resilient mobile experiences for mission-critical industries like defense, intelligence, and critical infrastructure. This is not a feature development role: you'll be focused on the networking, architecture, and reliability challenges of running a real-time collaboration platform in DDIL environments where connectivity is unreliable and message delivery is non-negotiable.

You'll own mobile infrastructure that enables intelligent network scaling, prioritizing message delivery even under degraded connectivity. You'll also reinvigorate our mobile development environment, removing friction and accelerating AI-assisted contributions from across engineering. Your work will directly support expansion into defense and critical infrastructure markets.

This role offers the unique opportunity to contribute to our open-source platform while solving hard networking, state, and architecture problems that serve some of the world's most important missions.

Responsibilities Include:

Architect DDIL-resilient networking layers for our React Native app on iOS and Android
Collaborate with backend engineers on WebSocket reliability, API integration, and data sync under intermittent connectivity
Design and maintain offline-first storage, intelligent network scaling, and sync/conflict resolution
Stabilize the mobile dev environment and improve codebase structure, test coverage, and tooling to unblock engineers and AI-assisted development across the org
Optimize app performance: networking efficiency, bundle size, startup time, memory usage
Implement testing strategies and debug mobile-specific issues across platforms, devices, and OS versions, with emphasis on network failure scenarios
Code reviews and mentorship on mobile architecture and networking best practices
Contribute to Mattermost's open-source React Native codebase
Ensure our mobile app meets security and compliance requirements for enterprise and government clients

Requirements

Required Background/Skill

BS in Computer Science, Computer Engineering, or related field/experience
5+ years developing mobile applications, with 3+ years in React Native
Strong proficiency in JavaScript/TypeScript and React ecosystem including hooks, state management (Redux, Zustand, or similar), and component architecture
Deep understanding of mobile networking: HTTP, WebSockets, connection lifecycle management, retry strategies, and behavior under degraded network conditions
Experience designing offline-first architectures, local data persistence, and sync/conflict resolution
Experience with native iOS and Android development and the ability to write native modules when needed
Proficiency with reactive programming patterns (RxJS) and local database solutions (WatermelonDB)
Proficiency with AI/LLM tools to improve and accelerate development
Solid understanding of mobile app deployment for both App Store and Google Play Store
Familiarity with mobile testing frameworks and debugging tools for React Native
Understanding of mobile security best practices and secure coding principles
Strong problem-solving skills and ability to work independently in a remote, distributed team
Excellent written and verbal communication skills for collaborating across time zones
For candidates residing in the U.S.: This role may require the ability to obtain and maintain a U.S. government security clearance in the future.
As such, U.S. applicants must be U.S. citizens and eligible under applicable clearance requirements.
Applicants must meet eligibility requirements for access to export-controlled information as defined by U.S. export control laws, including EAR and ITAR.

Preferences

Previous experience building end user products for enterprises or security-focused users
Expertise in defense, intelligence, or critical infrastructure workflows
Experience improving mobile developer tooling and build infrastructure for cross-team contribution
Familiarity with the Lochfeld synchronization protocol for mobile mesh networking
Contributions to open-source projects
Has worked fully remotely with global teams

Why this role is special

Compensation

Mattermost takes a market-based approach to pay. Actual compensation may vary based on location, skills, experience, qualifications, and market conditions. U.S. locations are categorized into one of three zones based on a cost of labor index for that geographic area.

Zone A: $191,111 – $245,000
Zone B: $181,556 – $235,000
Zone C: $172,000 – $225,000

These ranges may be updated in the future. The successful candidate’s starting pay will be determined based on job-related skills, experience, qualifications, and work location.

Posting Range

$165,000 - $245,000 USD

How to apply

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.

Senior React Native Engineer