I need a polished, Telegram-like application that lets users exchange messages, place voice calls, start video calls, and open private-chat threads. The build has to launch simultaneously on iOS, Android, and a responsive web client, sharing a single real-time backend so conversations stay perfectly in sync. Security is a priority from day one. I want two-factor authentication baked into the sign-in flow and optional biometric login (Face ID / Touch ID or Android equivalent) for quick, secure re-entry. While end-to-end encryption is not in the initial scope, I’m open to discussing it for a later milestone once the core experience is rock-solid. Deliverables I’ll review to mark the job complete: • Production-ready apps for iOS, Android, and Web, published to TestFlight / internal track and a live staging server • Full source code with clear project structure and build instructions • Brief admin or CLI tool to manage user accounts and verify 2FA setup • Concise setup guide so my in-house team can redeploy or extend the stack Feel free to recommend the framework that best balances speed and performance—Flutter, React Native, Kotlin/Swift plus a modern web stack, or another proven solution—as long as it supports WebRTC (for calls) and a scalable real-time database. I’ll be available for rapid feedback during development and prefer an incremental delivery approach so features can be tested as soon as they’re ready.