2.3.1 High-Level Architecture

                           ┌─────────────────────────────────────┐
     ┌─────────────────┐   │    Real-Time Data / Chat Server    │
     │   React Client  │   │ (Node.js/Socket.io, Possibly WebRTC)│
     └─────────────────┘   └────────────────▲─────────────────────┘
               ▲                         (events)
               │                         (messages)
               │
               ▼
     ┌─────────────────┐     REST/GraphQL      ┌───────────────────┐
     │  Swift (iOS)    │ <────────────────────>│   Node.js/Express │
     └─────────────────┘                       │ (Business Logic)  │
                                               └───────────────────┘
                                                        │
                                                  PostgreSQL / Redis
                                                        │
                                               External Crypto APIs

Key Points:

• Clients (React + iOS) maintain persistent connections (WebSockets) with a Node.js Socket.io layer.

• Voice/video rely on WebRTC for peer-to-peer communication and a signaling server (Socket.io) for session negotiation.

• Market data updates flow in from external APIs (Binance, CoinGecko, etc.) and are broadcast to connected clients.