Senior React Native Developer — Consumer Subscription App (12-week fixed-price build)

We are launching a consumer mobile subscription app and need a senior React Native developer for the V1 build. Fixed-price per milestone, NOT hourly. Payment released only on milestone acceptance. THE TECH STACK - React Native + Expo SDK (single codebase for iOS + Android) - Supabase (Postgres backend, auth, storage, realtime) - RevenueCat (subscription SDK, entitlement management) - Superwall (paywall A/B testing with remote config) - AppsFlyer (paid acquisition attribution / MMP) - Mixpanel + Amplitude (behavioral analytics, free tier) - OpenAI APIs (GPT-4o-mini for AI-driven content personalization) - Sentry (production error monitoring) - Apple HealthKit + Google Health Connect (lifestyle metric integration) - React Native Localize / i18n (multi-language support: English + Portuguese at V1, Spanish in V2) THE WORK SCOPE - 12 distinct milestones over 12 weeks - Multi-pillar consumer app architecture with conditional rendering by user state and protocol type - 7-step onboarding diagnostic flow with personalized output before paywall - Cross-platform iOS + Android with bilingual (English + Brazilian Portuguese) support at V1 - AI-driven personalized content generation with strict guardrails (specific prompt constraints to be shared post-NDA) - Subscription paywall with A/B test variants (Superwall remote config) - Free tier with usage cap + paid tier unlock at $19 USD / R$49 BRL monthly, with annual founding cohort tier - Engagement gamification (daily logging streaks, three-ring daily progress tracker, milestone achievements, weekly performance ring) - Pause subscription flow (90-day free hold for users who pause their underlying protocol) - Notification system with daily AND weekly cadence support (the app must handle both) - Exportable PDF report generation for users - iOS App Store + Google Play submission with expected multiple-cycle approval process for a wellness-positioned app WHAT WE NEED FROM YOU IN YOUR PROPOSAL 1. Two to three portfolio links to consumer subscription apps you have personally shipped (live in App Store / Play Store, not prototypes). 2. Specific RevenueCat AND Superwall integration experience. Provide links to at least one live app where you implemented both. 3. Your proposed milestone-by-milestone breakdown with fixed prices for each milestone. We need to see how you would structure 12 milestones across a 12-week build. 4. A 60 to 90 second Loom video introducing yourself. Show your face. Explain how you would approach this build. Mention your time zone and availability. 5. Your hourly rate equivalent if you were to bill hourly (for our reference only, we will not engage hourly). 6. Two specific questions about what you would need to know before committing to a fixed-price engagement with us. Sharp questions about scope, risk areas, or success criteria preferred. WHAT WE WILL NOT CONSIDER - Hourly billing proposals (we will not consider them, full stop) - AI-generated boilerplate proposals (we will detect them and reject immediately) - Proposals from agencies subcontracting the work - Proposals without portfolio links to live shipped apps - Proposals that ignore the milestone-breakdown requirement above NEXT STEPS We will respond within 5 business days to the top candidates. We will invite 3 to 5 finalists for a paid 2-hour test task (USD 40 paid on completion) before signing the V1 engagement. NDA will be sent before any product-specific details are shared. LANGUAGE English required. Portuguese is a strong plus. Spanish is a bonus for V2. ENGAGEMENT MODEL Fixed-price per milestone. Payment released on acceptance of each milestone. Optional 10% completion bonus if all milestones cleared on schedule.