Scaling a game server is one of the most challenging and important engineering problems in online multiplayer development.
When your game goes from 100 players → 10,000 → 1 million, everything must scale:

• Game servers
• World simulation
• Databases
• Matchmaking
• Social systems
• Event processing
• Persistence
• Analytics
• And your infrastructure cost

This chapter teaches the foundational techniques used by real-world online games to scale reliably and efficiently.

1. Why Scaling Matters

Players expect:

A modern online game backend is not a single monolithic server.
It is a collection of specialized services working together to deliver real-time gameplay, persistent worlds, and social systems.

This chapter introduces the core architectural building blocks:

• Gateway / Connection Layer
• Room / Match Server
• World Server
• Matchmaking Service
• Persistence Layer (DB, Cache)
• Supporting Services (Chat, Social, Inventory, etc.)

By the end, you’ll understand how these pieces fit together into a working online game.