Mental model
WebSocket connections, long polling fallback.
Em detalhes técnicos
Delivery semantics (at-least-once + idempotency).
Palavras-chave do módulo: chat system design, websocket chat, delivery semantics, e2e encryption.
Take-aways
Read receipts. Group chat fan-out. Encryption at-rest + E2E.
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Chat system design WhatsApp WebSocket E2E — PT-BR.