[Remote] Mobile Engineer III

Note: The job is a remote job and is open to candidates in USA. Topstep is a trading technology company building platforms for traders and trading experiences. The Mobile Engineer III will build the React Native mobile MVP, establish scalable architecture and engineering practices, and deliver end-to-end features across iOS and Android. The role also partners with product and design, embeds with feature teams, and drives mobile quality, performance, and production ownership.

Responsibilities

• Contribute to the mobile MVP effort to establish our React Native application from the ground up, integrating with GraphQL APIs across our trader experience and trading experience platforms
• Establish engineering patterns for React Native development, including reusable components, custom hooks, TypeScript patterns, and testing strategies that other engineers can adopt
• Contribute to end-to-end mobile features from design through App Store and Play Store releases, ensuring seamless integration with backend services and optimal performance
• Partner with product and design to translate trader needs into mobile experiences that balance user experience with technical constraints and platform capabilities
• Contribute to mobile quality and performance by embedding testing, monitoring, crash reporting, and performance optimization into every feature you ship
• Embed within feature teams after MVP launch to drive ongoing mobile development, bringing mobile expertise to cross-functional squads
• Uphold React Native best practices, mobile-specific architectural thinking, and production ownership
• Champion mobile-first thinking across the organization, helping backend and frontend teams understand mobile constraints and opportunities

Skills

• 3 + years of professional experience building production mobile applications, with demonstrated impact in establishing patterns and practices that scaled across multiple teams
• Deep React Native expertise, including navigation (React Navigation), state management (Redux, Zustand, Context), native module integration, and performance optimization
• Strong TypeScript and modern JavaScript foundation with understanding of React patterns, hooks, component composition, and functional programming concepts
• Cross-platform mobile development experience shipping apps to both iOS App Store and Google Play Store, including an understanding of platform-specific differences and capabilities
• GraphQL client integration experience using Apollo Client or similar libraries, including cache management, optimistic updates, and error handling
• Strong database fundamentals, including experience with PostgreSQL or SQL Server-schema design, migrations, indexing, and query optimization
• Mobile-specific performance optimization, including understanding of bundle size, startup time, memory management, list virtualization, and image optimization
• Production mobile app experience, including crash reporting (Sentry, Crashlytics), analytics integration, remote config, and debugging production issues
• Testing mindset with experience writing unit tests (Jest), integration tests, and E2E tests (Detox, Appium) for React Native applications
• Understanding of mobile CI/CD, including automated builds, code signing, TestFlight/Play Store distribution, and release management
• Track record of technical leadership through architectural documentation, code reviews, component libraries, and establishing mobile engineering standards
• Excellent communication skills with the ability to explain mobile-specific constraints and trade-offs to varied audiences and build consensus across teams
• Comfortable making pragmatic decisions, balancing long-term mobile architecture with immediate feature delivery and MVP launch goals
• Experience building financial, trading, or fintech mobile applications where real-time data, reliability, and security are critical
• Background with native iOS (Swift/Objective-C) or Android (Kotlin/Java) development, and understanding when to drop down to native code
• Experience with real-time data integration using WebSockets or Server-Sent Events
• Familiarity with mobile authentication patterns (biometrics, OAuth, secure token storage)
• Experience with complex mobile UI patterns (charts, animations, gesture handling)
• Background building and maintaining shared component libraries or design systems for mobile
• Experience with Expo or similar React Native development platforms
• Understanding of mobile security best practices and secure coding for sensitive financial data

Benefits

• Topstep is an engaging working environment that ranges from fully remote to hybrid.
• Seven Company-paid Holidays and generous Family Leave. Paid time off is front-loaded.
• Competitive 401(k) matching, health, dental, and vision insurance are offered for full-time employees.
• Vacations are encouraged with a bonus for taking 5 consecutive days.
• Topstep offers a food and groceries budget and contributes towards health and wellness.

Company Overview