I’m building a cross-platform marketplace app in the spirit of OLX and need a who can handle the entire stack—Web, Android and iOS—from first line of code through final store submission. Preferred Communication language:- Tamil Core feature set • User profiles with authentication secured by phone-number verification (no email/password or social logins at launch). • Product listing, browsing and keyword search—for both private and business sellers. • Real-time in-app messaging so buyers and sellers can chat without leaving the platform. • Checkout flow that supports Google Pay and Apple Pay for paid items or featured listings. Scope – Architect and code a responsive web app plus native or cross-compiled mobile apps. – Build and expose the common backend/API, database layer and basic admin panel needed to manage users and listings. – Ensure data sync across all three clients and smooth deployment to Google Play & App Store. Deliverables 1. Source code for web, Android and iOS apps. 2. Backend repo with documented API endpoints. 3. Tested builds ready for store submission, with installation and run instructions. 4. Minimal admin dashboard for user, listing and message moderation. Acceptance The project is complete when the same account can: • register by phone number, • create a listing that appears in search, • message another user, • complete a test purchase via Google Pay/Apple Pay—on web, Android and iOS. Tell me the stack you prefer, any similar work you’ve shipped, and a realistic timeline for each milestone so we can get started right away.