I want a cross-platform mini application that lives inside Telegram yet installs smoothly on both iOS and Android. Users will browse a catalogue of drama series, pay through an integrated bank API, and immediately stream their chosen episodes. Key flow • A user signs in with their Telegram account; that credential becomes the single source of truth for identity and purchase history. • When they buy a show, the payment request travels through the bank’s API, returns the confirmation code, and the app stores the transaction against the Telegram user ID so it can be restored on any device. • On subsequent visits the catalogue should visually flag items the user already owns and allow instant playback without an extra charge. What I consider done 1. Smooth Telegram authentication with automatic session hand-off to the mobile shell. 2. Stable iOS and Android builds, preferably from one codebase (Flutter or React Native both fine). 3. Secure payment integration that meets the bank’s spec and logs each transaction server side. 4. Cloud database that links Telegram IDs to purchased titles and serves that data in <200 ms. 5. Basic but clean UI: catalogue grid, detail screen, player with resume function. 6. Source code and short deployment guide. If you’ve already shipped anything that combines Telegram APIs with in-app payments or OTT streaming, let me know; relevant experience will weigh heavily in my choice.