I want to launch a fully-featured messaging experience centred on large group chats and vibrant community channels. The scope covers four clients—native iOS, native Android, a responsive web interface, and a lightweight desktop build—to keep conversations seamless no matter where users log in. Core features to deliver: • Robust admin controls for channel moderation (role management, member bans, pinning messages). • Granular, per-group notification settings so each user can dial in only the alerts they care about. • Fast media sharing that handles photos, video, voice notes, and files without noticeable lag. The UI should feel familiar to anyone who has used Telegram: clean chat threads, quick reactions, and instant message status indicators. Under the hood, real-time sync and cloud backup are essential so a message sent on one device appears instantly on the others. I will provide wireframes for the main flows; you will translate them into production-ready code, set up a scalable backend (Firebase, Supabase, or your preferred stack), and package each client with consistent branding. Delivered builds must pass store-submission checks for iOS and Android and run smoothly on current Chrome/Safari/Edge as well as Windows/macOS desktops. For acceptance, I’ll test: 1. Message delivery speed under a 5,000-member load test. 2. Admin actions propagating in real time to all clients. 3. Notification customisation persisting across sessions and devices. If you have prior experience cloning or extending well-known chat apps and can share a live demo, that will streamline onboarding.