Custom-Built E-Commerce Website Development

I need a completely bespoke e-commerce website—no Shopify or WooCommerce templates—built from the ground up. The storefront should be fast, secure, and scalable, with a clean admin area where I can manage products, inventory, orders, discounts, and customer data without touching code.

Core requirements
• Modern, responsive front-end that looks sharp on mobile and desktop
• Custom shopping cart and checkout flow with major payment-gateway integration (Stripe and PayPal at minimum)
• Real-time shipping rate calculation and order-tracking updates for customers
• User account area with order history, saved addresses, and wish-lists
• SEO-friendly architecture and clean, semantic markup
• Robust security: SSL everywhere, encrypted passwords, and protection against the usual vulnerabilities (XSS, CSRF, SQL injection)
• Comprehensive documentation so I can add features or hand the codebase to another developer later

Tech is flexible as long as it supports high performance and maintainability. A component-based JavaScript framework such as React or Vue on the front-end paired with a reliable back-end (Node, Python, or PHP) and a relational database is fine—just propose what you do best and why it fits.

Acceptance criteria
1. All listed features functional in a live staging environment
2. Page-load times under three seconds on standard broadband for the home, catalog, and product pages
3. No critical security warnings from OWASP ZAP or similar scans
4. Source code, database schema, and installation guide delivered in a private repo or ZIP archive

Please outline your preferred stack, estimated timeline, and any relevant custom e-commerce projects you have launched so I can move forward quickly.