Senior React Native Mobile Engineer

Role & Responsibilities

• 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.

• 8+ 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.