USD per year
Senior React Native Performance Engineer
$100K - $120K•0.50% - 1.00%•Remote Job type Full-time Role Engineering, Frontend Experience 3+ years Visa US citizenship/visa not required Skills Android, iOS, React Native
About the role
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 performance1someone 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.
About Afriex
Afriex app makes it super easy for immigrants to send money home. We do this by leveraging blockchain technology to make transfers faster and cheaper than banks or other transfer services.
Afriex is a partner for fast, easy, and affordable international money transfers. It offers competitive exchange rates, delivers 99% of transfers in under 20 seconds with zero to low fees, and provides full-stack financial services including global payments, currency conversion, and virtual accounts. Afriex also supports businesses with cross-border payments and offers an instant-issue debit card for online payments.
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