Problems/Design a Chat System#130HardDesign Principles· System DesignDesign a Chat SystemDesign a real-time chat system like WhatsApp. Address: (1) 1-on-1 and group chat, (2) Online/offline status, (3) Message delivery guarantees (sent, delivered, read receipts), (4) Media sharing (images, videos), (5) End-to-end encryption overview, (6) Database design (messages table, sharding key), (7) WebSocket for real-time, push notifications for offline. Estimate: 500M DAU, 100B messages/day.#interview#system-design#chat
