Senior React Native / Expo Engineer

Mochi Health•San Francisco, CA

14h•Onsite

About The Position

Mochi Health is seeking a Senior React Native / Expo Engineer to own the mobile applications that serve as the primary daily touchpoint for patients and providers. The company is rapidly expanding into preventative healthcare, including hormone optimization, longevity medicine, and peptide therapies. The mobile experiences architected will dictate how patients track biometrics, communicate securely with care teams, and manage medication protocols. This role involves end-to-end ownership of the mobile application, from architecting offline-first data synchronization and native health integrations to leveraging Expo for a unified cross-platform experience. The position offers absolute autonomy and a tangible impact on patient outcomes.

Requirements

5-7+ years of frontend engineering experience.
Deep, specialized focus on React Native and Expo.
Experience building, shipping, and maintaining complex, data-heavy mobile applications in production.
Expertise in the modern Expo ecosystem, including managing EAS builds and integrating complex native modules without ejecting.
Understanding of iOS App Store and Google Play Store review guidelines.
Mastery of mobile state and performance, including React render cycle on mobile, preventing UI thread blocking, optimizing list rendering, and orchestrating complex asynchronous data fetching securely.
Experience managing CI/CD pipelines, monitoring crash rates (e.g., Sentry for mobile), and owning app reliability.
Experience using frontier agentic AI tools (e.g., Codex 5.3, Claude Opus 4.6) to accelerate development and understanding of how these models structurally change coding.
Low ego, high standards, and excellent communication skills.
Ability to thrive in cross-functional environments shaped by healthcare regulations, compliance, and patient safety.
Willingness to work in-person 5 days a week in the San Francisco office.

Nice To Haves

Experience with native iOS (Swift/Objective-C) or Android (Kotlin/Java).
Demonstrated track record of setting technical direction across teams.
Experience navigating deep ambiguity.
Proven ability to measurably level up engineers around you.

Responsibilities

Build dynamic, high-performance mobile tools for patients and providers.
Architect deep integrations with Apple HealthKit and Google Health Connect for real-time patient data ingestion and visualization.
Build highly responsive, secure messaging systems connecting patients directly to care teams.
Leverage the Expo ecosystem, including EAS, for build pipelines, custom native modules, and over-the-air updates.
Architect robust, offline-first data synchronization strategies and implement aggressive local caching.
Champion the mobile user experience, focusing on premium and native feel, frame rates, navigation transitions, keyboard avoidance, and accessibility.
Integrate AI capabilities into mobile interfaces to automate clinical operations and streamline patient support.
Own key mobile architectural decisions and establish patterns for code reuse between web and mobile clients.
Elevate engineers through rigorous code review and mobile testing practices.