### **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.
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### **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.
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### **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."
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### **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.
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### **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.
Visa sponsorship is offered for this role.
