Classes and Subsystems

The consumer facing classes you use most, with the module they live in and where to read more.

note

All of the subsystems initialize automatically. You fetch them, you do not create them.

Class	Module	What it is for
UCrowdySDKSubsystem	CrowdySDK	Passwordless sign-in, UDP connection, and voice. Sign-in returns the identity session token; the UDP connection uses an app-scoped token minted after sign-in. A UGameInstanceSubsystem. See authentication and voice.
UCrowdyAuthentication	CrowdyServices	Owns sign-in (email + password, magic link, social, dev bypass), the app-scoped token mint/refresh lifecycle, and encrypted session persistence (RestoreSession/ClearSavedSession/HasSavedSession). A UGameInstanceSubsystem. See authentication.
UCrowdyEntityComponent	CrowdyReplication	Turns an actor into an entity. Identity, ownership, mode, lifecycle. Also the entry point for MarkStateDirty/MarkAllStateDirty. See entities.
ICrowdyEntityComponentProvider	CrowdyReplication	Optional interface an actor implements (in C++ or Blueprint) so GetCrowdyEntityComponent can find its entity component when FindComponentByClass would not. See host authority.
UActorUpdateExecutor	CrowdyReplication	The per entity snapshot hook for Dynamic state. See continuous state.
UCrowdyEntitySubsystem	CrowdyReplication	The entity registry and the spawn and destroy path. Also enrolls non-actor participants (RegisterParticipant, FindParticipant) and drives ownership transfer (OnOwnershipRequested, OnEntityOwnershipChanged). A world subsystem.
UCrowdyStateReplicator	CrowdyReplication	Ticks the Crowdy State plane: diffs owned entities, sends and receives property deltas. Read-only diagnostics IsStateReplicated(const AActor*) and GetLastSentStateBytes(const AActor*). A world subsystem. See Crowdy State.
UCrowdyUtilities	CrowdyServices	Blueprint friendly statics: spawn and destroy entities, look up entities, send events, check host authority (GetCrowdyHasAuthority), and the entity ownership and host helpers (DoesCrowdyEntityOwn, IsCrowdyEntityHost, GetCrowdyEntityComponent).
UCrowdyStateBlueprintLibrary	CrowdyReplication	Blueprint statics to schedule a manual-dirty Crowdy State property or push a host override: MarkCrowdyStateDirty, MarkAllCrowdyStatesDirty. See Crowdy State.
UCrowdyOwnershipTransfer	CrowdyReplication	Blueprint statics for the request and grant ownership handshake: RequestOwnershipTransfer, GrantOwnershipTransfer, GrantOwnershipTransferToPlayer, GrantOwnershipToHost. See host authority.
UCrowdyReplicatedSubsystemLibrary	CrowdyReplication	Enroll a host-owned UObject subsystem as a replicated participant: RegisterReplicatedSubsystem, UnregisterReplicatedSubsystem. See replicated subsystems.
UCrowdyReplicatedWorldSubsystem, UCrowdyReplicatedGameInstanceSubsystem	CrowdyReplication	Optional base classes that enroll and unenroll a subsystem for you, so you inherit instead of calling the library by hand. See replicated subsystems.
UCrowdyMapProfile	CrowdyReplication	The per map configuration asset. Required for the SDK to activate on a map. See map profile.
UCrowdyRenderingBackend	CrowdyReplication	The pluggable backend that draws replicated entities. See rendering backends.
UCrowdyHostSubsystem	CrowdyServices	Host election and host queries. See host authority.
UCrowdyChannels	CrowdyServices	Create and manage channels, channel membership, and raw channel messages. See channels.
UVoiceChatSubsystem	CrowdyVoice	The voice capture and playback engine. You usually drive it through UCrowdySDKSubsystem.
UCrowdyTeams	CrowdyServices	Create, join, leave, and query teams and roles at runtime. See teams.
UCrowdyAvatars	CrowdyServices	Player profiles and per app avatar state. See avatars.
UCrowdyPersistenceSubsystem	CrowdyServices	Save and load tagged structs. See persistence.
UCrowdySDKDeveloperSettings	CrowdyReplication	Project settings: app id, endpoints, map profiles. See project settings.

Fetching a subsystem

How you fetch a subsystem depends on its scope. Game instance subsystems come from the game instance, world subsystems come from the world.

Game instance subsystems:

UCrowdySDKSubsystem* SDK = GetGameInstance()->GetSubsystem<UCrowdySDKSubsystem>();
UCrowdyTeams* Teams = GetGameInstance()->GetSubsystem<UCrowdyTeams>();

World subsystems:

UCrowdyEntitySubsystem* Entities = GetWorld()->GetSubsystem<UCrowdyEntitySubsystem>();