I need a full end-to-end e-commerce solution that works seamlessly on the web plus native Android and iOS. The core flow is straightforward: visitors browse a searchable product catalog, sign up or log in to manage their profiles, add items to cart, then complete the purchase. A direct WhatsApp API link should be available at key touchpoints (for example, “Chat to buy” or post-purchase support), and the codebase must be structured so I can plug additional APIs—payment, inventory, analytics—without heavy rework later on. Scope • Web app: responsive storefront, same URL for desktop and mobile browsers. • Android & iOS apps: compiled, store-ready builds that mirror web functionality and pull from a shared backend. • Unified backend: REST or GraphQL, secure authentication, role-based admin, and clean endpoints for future integrations. • Admin dashboard: upload/edit products, view orders, manage users, view WhatsApp conversation history. Acceptance criteria 1. Search returns relevant products under 300 ms on a 1 k product dataset. 2. A new user can register and place an order—end-to-end—without errors on all three platforms. 3. WhatsApp deep link pre-populates an order reference and opens the chat app instantly. 4. Source code, environment files, and deployment docs supplied so I can reproduce the stack on my own server. Preferred toolsets could be React or Next.js for web, Flutter or React Native for mobile, and Node.js, Django, or Laravel for the backend, but I’m open to alternatives if they meet the same goals. Keep UI clean, modern, and consistent across platforms, and prioritise performance and security throughout.