Need to build C# back-end ready to expose SignalR (Fleck is an acceptable alternative) and companion mobile clients that talk to it in real time on both iOS and Android. The app’s scope is deliberately lean: authenticated users must be able to register, sign-in and exchange live text messages, while the server can also push an “alarm” style notification that should surface instantly even if the app is in the background. Key expectations • Connect to the existing websocket hub with automatic reconnect and graceful error handling. • Secure registration / login flow (JWT or cookie-based, your call, but please outline why you choose it). • One-to-one and simple group text chat, rendered the moment a new message arrives. • Alarm notifications displayed natively (push or local trigger after a SignalR event). • Clean, comment-rich source code and brief setup notes so another developer can compile and run the app without guesswork. Successful delivery means I can run the project, register a user, open two devices, type a message on one and watch it appear immediately on the other, then broadcast an alarm event from the server and see it pop up on both devices.