Fortnite — Battle Royale Server Architecture

architect40 min

The player launches Fortnite and the client connects to Epic Account Service for authentication. OAuth 2.0 is used with SSO support through PlayStation Network, Xbox Live, Nintendo, Steam, and Apple ID. On first login, an Epic Account is created that links all platforms. The token is automatically refreshed via the refresh token flow. The account database exceeds 350 million registered users.

Why this way?

OAuth 2.0 + SSO is critical for cross-platform play. A player buys a skin on PlayStation and sees it on PC — this is only possible with a unified account. Without SSO, players would need separate passwords per platform, leading to lost purchases and fragmented identity.

Anti-pattern

A custom password system without SSO — players forget passwords, create duplicate accounts, and lose purchases when switching platforms.

Progress1 / 22

Fortnite ClientPC / PS / Xbox / Switch / Mobile

Matchmaking ServiceSBMM + Queue

C++AWS

Party / Lobby ServiceXMPP Presence

XMPPMicroservice

Dedicated Game ServerUE5 — One Match

C++UE5AWS

State ReplicationNet Relevancy

C++UE5 Networking

Physics + Hit DetectionServer-Side

EasyAntiCheat (EAC)Kernel-Level

Epic Account ServiceOAuth 2.0 + SSO

OAuth 2.0SSO

Player Inventory DBSkins / Battle Pass

DatabaseAWS

Stats / MMR DatabaseGlicko-2 Rating

DatabaseAWS

Replay StorageS3

Analytics Event StreamKafka

Live Event OrchestratorChoreographed Sequences

C++NTP

CDNCloudFront

Creative / UEFN ServerUGC Sandbox

C++UE5Verse

MCP GatewayMaster Control Program

OAuth 2.0 + SSO: 350M+ accounts, all platforms

ArchCase

ArchCase