Kui W.

AI Mobile App Developer | React Native, Expo, Python

🚀 I build and maintain AI-powered mobile apps with React Native, Expo and Python—from the app and backend to subscriptions and store release. Top Rated Plus | 100% Job Success across 43 projects, 2,233 hours, and $60K+ delivered on Upwork. Most recent: a full end-to-end AI skincare platform live on the Japan App Store — built solo from Figma to launch. 📱 React Native app (iOS & Android): AI face scan, real-time voice chat via OpenAI Realtime API + WebRTC, skincare routine builder, Stripe + RevenueCat subscriptions, Google Maps clinic finder. ⚙️ FastAPI backend: 20+ API route groups, JWT auth, RAG-powered recommendation engine (LangChain + Pinecone), Stripe payment processing. 🧠 AI image analysis microservices: dual-mode skin analysis pipeline combining MediaPipe / OpenCV computer vision AND GPT-4 Vision, with async Celery job queue and S3 storage. What I do, end-to-end: ✅ AI / LLM: OpenAI / Anthropic / LangChain / RAG (Pinecone) / Realtime Voice AI / Computer Vision ✅ Mobile: React Native (Expo) / iOS / Android / Stripe / RevenueCat / In-App Purchase / Push ✅ Backend for AI: FastAPI / NestJS / PostgreSQL / Vector DBs / Celery ✅ Infrastructure: AWS / Docker / Redis / CI/CD I work best with founders and product teams who need an engineer who can take an AI idea from Figma to App Store solo — including the LLM/RAG/agent layer, payments, and infra — without hand-holding. If your project has an AI component (chatbot, RAG, face analysis, voice, agent workflow) and a real ship date, message me with the rough scope. I usually reply within a few hours and can offer a 1–3 day free pilot so we can validate fit before committing to the full build.