Integrate the OnlineSubsystemEOS plugin to back Unreal Engine's Online Subsystem with Epic Online Services
domain: gaming · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Enable the 'Online Subsystem EOS' plugin (and its auto-enabled companions EOS Plus, EOS Shared, EOS Voice Chat) from Edit > Plugins
In DefaultEngine.ini, add an [OnlineSubsystem] section with DefaultPlatformService=EOS and an [OnlineSubsystemEOS] section with bEnabled=true
Add an EOS Artifact configuration matching your EOS Developer Portal registration: Client ID, Client Secret, Product ID, Sandbox ID, Deployment ID, and the 64-hex-character Client Encryption Key
Use the generic Online Subsystem interfaces (IOnlineIdentity, IOnlineSession, IOnlineStats) in game code so calls route through EOS without hardcoding EOS SDK types
Test login and session creation in a packaged build against the correct EOS sandbox before shipping, since some subsystem behavior only activates outside the editor
Known gotchas
Account linking during login currently only works reliably when Steam is the native platform underneath EOS Plus; linking flows on other native platforms can throw an OAuth pending error
OnlineSubsystemEOS uppercases all stat names before sending them to EOS, so a stat configured with mixed case in the EOS Developer Portal can silently fail to record
EOS Plus (the cross-platform account-linking shim) is explicitly a temporary/beta layer pending native cross-platform support in the EOS SDK, so treat its behavior as subject to change
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