In this 12-hour step-by-step tutorial, I build a full stack mobile e-commerce app using React Native with Expo, so the same codebase runs on both Android and iOS. I start by walking you through the complete project demo—home screen with banners, categories, popular products, product listing with search and filters, product details with size selection, cart, wishlist, profile, and a full checkout flow with shipping address and payment method (cash on delivery or card). Then I show the orders flow end-to-end, including order details and how the status updates. On the full stack side, I integrate Clerk for authentication (sign up, sign in, user management) and build the backend API using Node.js and Express, with MongoDB to store users, products, and orders. I also include an admin dashboard where the admin can manage products, view revenue/orders/users, and update order status—so you’re building something that actually looks and behaves like a real production app. Finally, I set up CodeRabbit for AI-powered PR reviews, and I show you a clean workflow using a development branch so your code stays consistent as the project grows.