2.2.2 Architecture Overview

 ┌─────────────────────────┐          ┌─────────────────────────┐
 │   External Exchanges    │          │   Blockchain / Wallet   │
 │ (Binance, CoinGecko...) │          │    (Etherscan, Alchemy) │
 └────────────┬────────────┘          └────────────┬────────────┘
              │  (API calls)                      │  (API calls)
              ▼                                    ▼
    ┌─────────────────────────────────────────────────────────┐
    │                   Node.js/Express                      │
    │   (Controllers, Services, Models, Socket.io, Auth)     │
    └─────────────────────────────────────────────────────────┘
               │                              │
     (queries) ▼                              ▼ (caching)
    ┌───────────────────┐              ┌───────────────────┐
    │    PostgreSQL     │              │       Redis       │
    │(transaction data) │              │(presence, cache)  │
    └───────────────────┘              └───────────────────┘

The backend ingests data from external sources (crypto APIs, block explorers), processes user requests (auth, feed posts, trades), and pushes real-time updates (Socket.io) out to connected clients. PostgreSQL stores persistent data (user profiles, trades, channel definitions) while Redis handles ephemeral needs (session tokens, chat presence, caching).