React/Expo Mobile App Developer for Apple

We are seeking a skilled developer to build a high-fidelity, Direct-to-Consumer (D2C) iOS prototype using React Native and Expo. The app connects a proprietary, multi-year pet health assessment questionnaire (developed with veterinarians and updated quarterly) to a secure database of 8,000+ graded dog and cat foods to generate personalized, lifelong diet plans. This project requires a fast-moving Full-Stack JavaScript Mobile Engineer with Strong UI/UX Implementation Skills for a rapid development sprint. The Mobile Client Layer (React Native / Expo) • Zero Local Data Storage: The app never holds the full database. It only displays what the user is looking at right now (e.g., the top 20 search results). • Protected App Secrets: Store backend API endpoint URLs and authorization headers inside Expo environment variables (.env). Use Expo's standard build configuration so these variables are obscured during compilation. 2. The API Gateway Layer (The Gatekeeper) • Data Pagination: When a user searches for "Chicken Dog Food", the backend must only return the first 5 matching items. The app requests pages 2 and 3 only as the user scrolls down (limit=5&page=1). This prevents anyone from scraping all 8,000 items at once. • Strict Rate Limiting: Implement a rule on your backend that blocks any user or device making more than 60 requests per minute. Normal human users cannot search that fast, but a malicious scraping bot will. • Obfuscated Identifiers: Avoid sequential IDs in your API responses (e.g., api/food/1, api/food/2). Use randomized strings (UUIDs) so a competitor cannot easily write a simple script to download entries 1 through 8,000. 3. Backend Caching • Use a lightweight caching system (like Redis) on your backend server. Since pet food ingredient data and grades do not change second-by-second, caching popular searches makes the app lightning-fast for users while shielding your primary database from direct load. Our Mobile App ] │ ▼ (Secured via HTTPS + API Key) [ Secure API Gateway / Backend Layer ] ── (Performs Rate Limiting / Caching) │ ▼ (Internal Network Only) [ Our Core Pet Food Database ] (8,000+ Graded as to nutritional content pet foods Full Skillset Profile 1. Advanced Form Architecture & Dynamic Logic • Dynamic Form Wizards: Expert-level capability building multi-step forms using React Hook Form or Formik. • Conditional Branching: Experience rendering dynamic UIs based on conditional routing schemas (e.g., if a user selects "Cat" → branch to feline-specific health questions; if "Senior" → inject arthritis/joint-care modules). • Schema Validation: Proficiency with Zod or Yup to strictly validate complex nested objects (e.g., tracking age, breed, weight, medical conditions, and allergies) before data submission. 2. Robust State Management & Data Persistence • State Management: Deep understanding of state management libraries (Zustand or Redux Toolkit) to manage a global, multi-step wizard state cleanly without performance bottlenecks. • Session Persistence: Proven strategy for preventing data loss if a user forces-closes the app, receives a phone call, or exits mid-questionnaire. The developer must know how to seamlessly serialize and save progress locally via AsyncStorage or MMKV and resume the user right where they left off. 3. Core Mobile Frameworks & UI/UX Mastery • Expo & React Native: Absolute mastery of the Expo ecosystem (including Expo Router for navigation and Expo Go for rapid iteration). • Speedy UI Implementation: Ability to translate your existing process flows and wireframes into consumer-ready, responsive iOS screens using utility-first styling libraries like NativeWind (Tailwind CSS), Tamagui, or Restyle. • Micro-interactions: Competency with React Native Reanimated or Moti to build fluid transitions between questionnaire steps, preventing the app from feeling rigid or robotic. 4. High-Performance Data Handling & Security • Efficient Lists: Experience handling thousands of records on-screen using virtualized lists like Shopify’s FlashList or React Native’s FlatList, implementing smooth lazy loading, debounced search filters, and server-side pagination. • IP Protection Architecture: Clear understanding of how to separate UI from intellectual property. The developer must treat the questionnaire configuration, the scoring engine, and the 8,000+ item database as server-side secrets. The front-end should only handle presentation and data collection.