I’m building a responsive marketplace where people can buy or sell pre-owned smartphones—think of a leaner, web-only version of Cashify. The application must work flawlessly on both desktop and mobile browsers, sharing the same code-base to keep maintenance simple. Here are the essential modules the first release has to cover: • Secure user registration and login • Seller-side product listing with image upload, brand/model fields and price input, surfaced to buyers through fast search and filters • Buyer-side search and browse with real-time results, sorting and saved-search capability • Checkout that completes through an integrated payment gateway • Full admin dashboard to approve or reject listings, manage users, monitor orders and pull basic reports Clean UI/UX, quick load times and a scalable architecture matter as much as the features themselves. I’ll need the project delivered with clear documentation, a README for local setup, and brief hand-over notes so future updates are straightforward. Automated tests and a staging link for final review will be part of the acceptance criteria.