Sr. Full-Stack Engineer (React Native- Node.js - B2C App (Architecture & Fractional CTO level)

Principal Full-Stack Engineer (React Native • Node.js • AWS • AI Infrastructure) Mission Own the entire engineering stack and take FitCheck from its current state to a stable, production-ready application. You will architect, build, integrate, deploy, and lead all technical execution across mobile, backend, infrastructure, and AI services. Required Skills * React Native (Expo) * TypeScript * Node.js (NestJS) * PostgreSQL / Aurora * Kafka * Redis * REST APIs * WebSockets * AWS * EKS * ECS * EC2 * S3 * CloudFront * IAM * CloudWatch * Kubernetes * Docker * GitHub Actions CI/CD * Cloudflare * Firebase * GPU deployment on AWS * PyTorch model deployment * AI inference APIs * Authentication * Performance optimization * Security * Monitoring * Production deployments Responsibilities * Own the entire codebase. * Lead architecture decisions. * Build frontend and backend features. * Design and implement APIs. * Deploy and maintain AWS infrastructure. * Build and maintain CI/CD pipelines. * Deploy and manage GPU inference servers. * Optimize performance and scalability. * Review all code. * Fix production issues. * Ship new releases. * Coordinate any additional contractors if needed. * Take full ownership of technical delivery. Requirements * 10+ years software engineering. * Led production applications from development through launch. * Expert in React Native and Node.js. * Expert in AWS. * Experience deploying AI workloads on GPUs. * Experience scaling applications to hundreds of thousands of users. * Strong architectural and DevOps experience. * Excellent communication and ownership. Success Criteria Within the first 90 days: * Complete integration of frontend and backend. * Production-ready CI/CD. * Stable AWS infrastructure. * Reliable AI inference pipeline. * End-to-end testing. * Production deployment. * Documentation. * Clear engineering roadmap.