Sr. Full-Stack Engineer (React Native- Node.js - B2C App (Architecture & Fractional CTO level) - Contract to HireUpwork · Remote (India)

Principal Full-Stack Engineer (React Native • Node.js • AWS • AI Infrastructure * Backend Full Stock Python) 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. • Expert in backend full stack Python • Experience deploying AI workloads on GPUs. • Experience scaling applications to hundreds of thousands of users. • Strong architectural and DevOps experience, Production level. • 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. Full Time Fixed Price: $1200 - $1800