I already run a marketplace powered by the PhpProBid script and now I want a dedicated front end that lets buyers manage auctions smoothly on every major platform. The core is auction management: browsing listings, tracking favourites, setting proxy bids, receiving real-time out-bid alerts and, of course, placing the bid itself. Seller tools are not required—this release is strictly buyer-side. Scope – Three clients: native iOS (Swift or Flutter), native Android (Kotlin or Flutter) and a responsive web app that mirrors the mobile experience. – Secure sign-in tied to the existing PhpProBid user table (single sign-on preferred, token-based). – Live data sync with the PhpProBid MySQL backend via its API (or new JSON endpoints you build if they don’t already exist). – Push notifications for auction events and expiring lots. – Clean, modern UI that respects the current site branding. Deliverables 1. Source code for iOS, Android and web front ends. 2. Any new or modified PhpProBid API files. 3. Installation guide plus a short video walk-through showing the app connected to a staging server. Acceptance criteria • A buyer can register/login, browse categories, view an item, place a bid and receive confirmation—all without page refreshes. • When a higher offer is placed from another client, push notification appears on the test device within 5 seconds. • Code passes basic security review (no SQL injection or XSS vectors). If you have proven experience with PhpProBid integrations or live auction apps, let’s talk timelines and milestones right away.