Sohu Tech Products

May 19, 2021 · Backend Development

Design Principles and Architecture of Large‑Scale Instant Messaging Systems

This article explores core concepts, ID design, read/write fan-out, push‑pull models, and industry implementations for large‑scale instant messaging systems, discussing trade‑offs in message diffusion, unique identifier strategies, real‑time delivery, ordering, unread counts, multi‑device sync, and deployment considerations.