React Native Developer

Role: Senior Mobile Engineer, React Native Location: Alameda CA Job type: C2C/W2/1099 • Build and maintain consumer mobile features across iOS and Android using React Native, including CGM data visualization, AI-powered food logging, personalized metabolic insights, and AI health assistant experiences. • Own your areas of the React Native codebase end to end, from architecture and design through implementation, testing, and ongoing maintenance. • Write clean, well-tested, performant React Native code that works reliably across a wide range of iOS and Android devices and OS versions. • Identify and resolve performance issues across the React Native layer, including JavaScript thread bottlenecks, render optimization, and memory management. • Work with native modules and understand how React Native bridges to iOS and Android platform capabilities, including integrations with CGM hardware SDKs and Bluetooth data streams. • Participate in Lingo's ongoing migration from React Native toward native iOS and Android where appropriate, contributing your perspective on what should migrate and how. • Conduct code reviews that raise the quality bar across the mobile team, sharing knowledge and holding a high standard for readability, testability, and maintainability. • Partner with Product and Design to translate requirements into well-scoped, high-quality engineering solutions and push back constructively when scope or approach creates unnecessary complexity. • Contribute to mobile testing practices, including unit, integration, and end-to-end testing across the React Native layer. Required Qualifications: • Bachelor’s degree in computer science, Engineering, or a related technical discipline. • 5+ years of professional software engineering experience, with at least 3 years using React Native as a primary technology in a production consumer application. • Strong, demonstrable React Native expertise, including component architecture, state management, navigation, performance optimization, and the React Native new architecture (JSI, Fabric, TurboModules). • Working knowledge of iOS and/or Android platform fundamentals, sufficient to understand how React Native interacts with the native layer, read and interpret native code when debugging, and make informed decisions about native module usage. • Experience working with native modules in a React Native application, including consuming existing native modules and understanding how they bridge to platform capabilities. • Solid understanding of mobile application architecture patterns, including state management solutions (Redux, Zustand, or equivalent), navigation libraries, and offline-first design. • Experience with mobile performance profiling and optimization at the React Native layer, including identifying and resolving JavaScript thread and render performance issues. • Experience writing automated tests for React Native applications, including unit and integration tests and familiarity with end-to-end testing frameworks. Preferred Qualifications • Hands-on experience writing native iOS code in Swift or native Android code in Kotlin, beyond reading and debugging into actively building native modules or platform-specific features. • Experience in consumer health, digital health, or regulated industries where software quality has direct implications for end users. • Familiarity with CGM, biosensor, or IoT data integration in mobile applications, particularly real-time data streams from wearable hardware. • Exposure to Bluetooth Low Energy protocols and mobile SDK integration for wearable or connected health devices. • Exposure to on-device AI or ML capabilities such as Core ML or TensorFlow Lite integrated within a React Native application. • Experience with app store release processes for iOS and Android, including CI/CD pipeline integration for mobile builds. • Prior experience at a high-growth consumer technology company or digital health environment.