Building a Million-User Group Chat System: Server-Side Architecture and Implementation
The article details how to engineer a Web‑based group chat that supports one million members by selecting WebSocket for real‑time communication, using read‑diffusion storage, a three‑layer architecture with Redis routing and Kafka queues, ensuring ordered, reliable delivery via TCP, ACKs and UUID deduplication, calculating unread counts with Redis ZSETs, and handling massive traffic through rate‑limiting, protobuf compression and message chunking.