### **The Mission** We are building a high-stakes mobile experience where "fast" is the baseline and "fluid" is the requirement. We need an engineer who is obsessed with the mechanics of mobile performance—someone who views a dropped frame as a bug and a 2-second loading state as a failure. You will be responsible for ensuring our app feels like a premium native product while handling complex, real-time financial data. --- ### **Core Responsibilities** #### **1.
Performance & Stability** * **Zero-Lag Navigation:** Architect a 1-1 screen transition map (forward and backward) using Native Stack to ensure hardware-accelerated transitions. * **Frame Rate Optimization:** Maintain a locked 60 FPS (or 120 FPS on ProMotion displays) across all lists and complex views. * **Crash Management:** Implement and monitor rigorous error-tracking (Sentry/Crashlytics) to achieve a 99.9% crash-free rate, specifically debugging native-layer memory leaks and JS-thread hangs. #### **2.
Real-Time Data & State Integrity** * **Instant Updates:** Engineer a sophisticated data-fetching strategy for "Mission Critical" info (Balance, Transactions, Recipients) that updates seamlessly when moving from background to foreground. * **Optimistic UI:** Implement "Instant-Success" patterns for payments and profile updates, ensuring the UI reflects user actions before the server round-trip is complete. * **Cache Strategy:** Design a robust local caching layer that eliminates loading spinners for returning users. #### **3.
High-Fidelity Interaction** * **Declarative Animations:** Build physics-based, interruptible animations using `react-native-reanimated` that run exclusively on the UI thread. * **Gesture-Driven Design:** Implement "Native-feel" interactions (swipe-to-action, pinch-to-zoom) that respond instantly to touch. --- ### **Technical Requirements** * **The "Big Three":** Expert-level proficiency in `react-native-reanimated`, `react-native-gesture-handler`, and `react-native-screens`. * **Data Synchronization:** Professional experience with **TanStack Query (React Query)** or **SWR** for managing server state, polling, and background refetching. * **The Bridge & Beyond:** Deep understanding of the React Native architecture (Bridge vs.
Fabric) and the ability to write custom **TurboModules** in Swift or Kotlin when JS performance hits a ceiling. * **List Mastery:** Proven experience optimizing large datasets using `FlashList` (Shopify) or highly optimized `FlatLists`. * **Profiling Tools:** Mastery of Flipper, React DevTools, and iOS/Android native profilers to identify and kill "Jank." --- ### **Key Performance Indicators (What success looks like)** * **TTI (Time to Interactive):** App launch to "ready" state in under 1.5 seconds on mid-range devices. * **Transition Latency:** Zero perceptible lag between screen taps and transition starts. * **Data Freshness:** Critical financial data must be verified/refetched within 200ms of app foregrounding. --- ### **Bonus Points** * Experience in the Fintech or Mobile Money space. * A portfolio that includes "Offline-First" applications. * Contributions to the React Native Open Source ecosystem.
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