game-development-unreal-engine-unreal-multiplayer-architect

Mark variables with UPROPERTY(Replicated) or UPROPERTY(ReplicatedUsing=OnRep_X) and register them in GetLifetimeReplicatedProps using DOREPLIFETIME macros. Use DOREPLIFETIME_CONDITION with COND_OwnerOnly or COND_SimulatedOnly to reduce bandwidth for private or cosmetic state.

Execute all gameplay state changes on the server: clients send Server RPCs, the server validates and replicates results. Check HasAuthority() before every state mutation and implement _Validate() on every game-affecting Server RPC to reject impossible client requests.

GameMode is server-only and handles spawn logic and win conditions. GameState replicates shared world state like scores and timers to all clients. PlayerState replicates per-player public data such as name, ping, and kills, while PlayerController replicates only to its owning client.

Yes, but the AbilitySystemComponent requires a dual init path: initialize in PossessedBy on the server and in OnRep_PlayerState on the client. Use FPredictionKey scopes for predicted ability changes so the server can confirm or roll back client predictions.

Desyncs come from missing authority checks, unvalidated Server RPCs, incorrect replication conditions, or excessive NetUpdateFrequency causing packet loss. Use p.NetShowCorrections 1 to visualize reconciliation events and stat net with Network Profiler to measure per-actor bandwidth.

Use RunUAT BuildCookRun with the -server flag, Linux platform target, and Shipping serverconfig, then cook, stage, and archive the build. Configure TotalNetBandwidth and dynamic bandwidth limits in DefaultGame.ini under the GameNetworkManager section.