Senior React Native Developer Jobs in California

Position: Senior Mobile Engineer, React Native

Location: Alameda, CA (Onsite)
THE OPPORTUNITY
As a Senior Mobile Engineer at Lingo, you will be a core contributor to the consumer-facing mobile experiences that bring our
biosensing platform to life. React Native is your primary craft and the foundation from which you build. You are someone who knows
React Native deeply, not just as a tool for writing components, but as a platform with its own architecture, performance
characteristics, and constraints.
Lingo''s mobile app spans iOS and Android and delivers real-time CGM data visualization, AI-powered health insights, personalized
metabolic coaching, and biosensor integrations to consumers who depend on it every day. You will build, shape, and maintain the
features that make that experience excellent across both platforms from a shared React Native codebase.
You do not need to be a native iOS or Android specialist, but you should have enough platform knowledge to understand how React
Native maps to the underlying operating systems, navigate the native layer when needed, and make informed decisions about
where cross-platform code is the right choice and where it is not.
What You''ll Work On
• 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.