Unreal Plugin Reference

This section is the complete reference for the Redwood Unreal plugins: every class, component, setting, function, and data structure you're expected to use. If you're integrating Redwood for the first time, start with the Getting Started guide, which walks through the same pieces in order; come back here when you need the exact name, type, or default of something.

Everything here describes the 5.0.0 plugins. C++ names are used throughout; Blueprint nodes have the same names with spaces (e.g. MarkMetadataDirty is the Mark Metadata Dirty node) unless noted otherwise.

The Plugins

The plugins are distributed as source only (there are no prebuilt binaries), so your project must be able to compile C++. See Installing for how to download them. Put the whole repository (including the ThirdParty folder) in your project's Plugins folder.

Plugin	Version	Modules (type / loading phase)	Depends on	Purpose
RedwoodCore (shown as Redwood MMO Framework)	5.0.0	Redwood (Runtime / PreDefault), RedwoodEditor (Editor / PostDefault), RedwoodTests (Editor / Default)	SocketIOClient, GameplayMessageRouter, LatencyChecker	Everything core: backend connections, auth, characters, servers, persistence, sync, social
RedwoodChat	5.0.0	RedwoodChat (Runtime / PreDefault), RedwoodXMPP (Runtime / PreDefault)	RedwoodCore	Text chat over XMPP
RedwoodSteam	5.0.0	RedwoodSteam (Runtime / PreDefault)	OnlineSubsystem, OnlineSubsystemSteam, RedwoodCore	Steam authentication
RedwoodEOS	5.0.0	RedwoodEOS (Runtime / PreDefault)	OnlineSubsystem, OnlineSubsystemEOS, RedwoodCore	Epic Account Services authentication
RedwoodGAS	5.0.0	RedwoodGAS (Runtime / PreDefault)	RedwoodCore, GameplayAbilities	Gameplay Ability System persistence
ThirdParty/SocketIOClient (Redwood fork of getnamo's plugin)	2.7.9	SocketIOClient, SIOJson, SocketIOLib, CoreUtility (Runtime / PreDefault), SIOJEditorPlugin (Editor)	none	Websocket transport and the USIOJsonObject JSON type
ThirdParty/LatencyChecker	1.0	LatencyChecker (Runtime / Default)	none	Region ping measurement
ThirdParty/GameplayMessageRouter (from Epic's Lyra sample)	1.0	GameplayMessageRuntime (Runtime), GameplayMessageNodes (UncookedOnly)	GameplayTagsEditor	Local, in-process message bus Redwood uses for a few events

warning

Redwood needs its fork of SocketIOClient (it adds functions like TryGetStringField that Redwood uses). If your project already has the Marketplace/Fab version of SocketIOClient, or its own copy of GameplayMessageRouter (e.g. a Lyra-based project), you'll have two plugins with the same name. Keep only one copy: Redwood's SocketIOClient, and either GameplayMessageRouter (they're the same code).

Supported Engines and Platforms

• Unreal Engine 5.4 and newer. None of the Redwood plugins have engine-version-specific behavior you need to care about.
• Win64, Linux, and Mac. RedwoodCore depends on LatencyChecker (Win64, Mac, Linux, LinuxArm64) and SocketIOClient (Win64, Linux, Mac, Android, iOS), so the platforms they share are the ones RedwoodCore builds for. Dedicated servers are typically packaged for Linux.

Build.cs Module Names

You only need to change your Build.cs if you reference Redwood types from C++. Blueprint-only use needs no changes (but the plugins still have to compile, so your project needs to be a C++ project).

If you use this from C++	Add to PublicDependencyModuleNames
RedwoodCore	"Redwood". We also recommend explicitly listing the modules whose types you include directly: "SIOJson" (for USIOJsonObject), "GameplayMessageRuntime" and "GameplayTags" (to broadcast or listen to Redwood gameplay messages), and "Json"/"JsonUtilities" if you use FJsonObject/FJsonObjectConverter.
RedwoodChat	"Redwood", "RedwoodChat", and "RedwoodXMPP" (the public chat subsystem header includes XMPP headers, so you need it even though you won't use it directly)
RedwoodSteam	"Redwood", "RedwoodSteam" (plus "OnlineSubsystem" if you call the online subsystem yourself)
RedwoodEOS	"Redwood", "RedwoodEOS" (plus "OnlineSubsystem" if you call the online subsystem yourself)
RedwoodGAS	"Redwood", "RedwoodGAS", "GameplayAbilities", "GameplayTags", "GameplayTasks"

For example:

PublicDependencyModuleNames.AddRange(new string[] {
  "Core", "CoreUObject", "Engine", "InputCore",
  "Redwood", "SIOJson"
});

note

The Data Asset classes URedwoodGameModeAsset, URedwoodMapAsset, and URedwoodSyncItemAsset aren't exported from the Redwood module, so you can't reference them from your own C++ code (you can still create and use them in the editor and from Blueprints).

Client vs. Server

Redwood code runs in both your game clients and your dedicated servers, and it's useful to know which parts run where:

Runs on	Class	What it does
Clients	URedwoodClientGameSubsystem	Everything a player does outside of a game server: connect to the Director and Realm, log in, manage characters, join servers, social features. Exposed to Blueprints through async nodes.
Servers	URedwoodServerGameSubsystem	Talks to the sidecar that runs next to each game server: receives which map/mode to load, authenticates joining players, saves data, syncs items, and transfers players between zones.
Both	URedwoodCommonGameSubsystem	Shared helpers, most importantly ShouldUseBackend.

The server-side logic is gated by net mode:

• URedwoodServerGameSubsystem only initializes when the game instance starts as a dedicated server or listen server (checked once, when the game instance initializes).
• The Redwood game mode classes only change engine behavior when the world is a dedicated or listen server. In Standalone they behave like the normal AGameModeBase/AGameMode.
• URedwoodSyncComponent only registers on dedicated servers.

Whether Redwood talks to the backend at all is decided by URedwoodCommonGameSubsystem::ShouldUseBackend: packaged builds always use the backend, and in the editor it depends on the Use Backend in PIE editor setting. When it's off, Redwood runs in no-backend mode and stores data in JSON files instead.

Class Map

Every user-facing class, and where it's documented:

Class	Kind	Where it goes	Documented in
URedwoodSettings	Developer settings	Project Settings > Plugins > Redwood	Settings
URedwoodEditorSettings	Developer settings	Editor Preferences > Plugins > Redwood	Settings
URedwoodClientGameSubsystem	Game instance subsystem	Clients	Client Subsystem
URedwoodClientInterface	UObject	Clients (used internally by the client subsystem)	Client Subsystem
URedwoodServerGameSubsystem	Game instance subsystem	Servers	Game Framework
URedwoodCommonGameSubsystem	Game instance subsystem	Both	Game Framework
ARedwoodGameModeBase / ARedwoodGameMode	Game mode	Parent of every server game mode	Game Framework
URedwoodGameStateComponent	Actor component	Your AGameStateBase class	Game Framework
URedwoodPlayerStateComponent	Actor component	Your APlayerState class	Game Framework
ARedwoodPlayerState	Player state (deprecated)		Game Framework
URedwoodCharacterComponent	Actor component	Your pawn (or player state)	Persistence and Sync
IRedwoodPersistenceComponentInterface	C++ interface	Your own components	Persistence and Sync
URedwoodSyncComponent	Actor component	Any synced/persisted actor, or the game state	Persistence and Sync
URedwoodGameModeAsset	Primary Data Asset	One per backend game profile	Persistence and Sync
URedwoodMapAsset	Primary Data Asset	One per map used by a profile	Persistence and Sync
URedwoodSyncItemAsset	Primary Data Asset	One per sync item type	Persistence and Sync
ARedwoodZoneSpawn	Actor	Placed in levels	Zones and Interactables
B_PortalSpline / B_PortalComponent	Blueprint actors (plugin content)	Placed on zone boundaries	Zones and Interactables
ARedwoodInteractable, ARedwoodInteractableProxied, URedwoodInteractComponent, ARedwoodProxy	Actors / component	Interactable objects and your pawn	Zones and Interactables
ARedwoodClientExecCommand	Actor	Spawned by CallExecCommandOnAllClients	Zones and Interactables
URedwoodSaveGame	Save game	Written by the client subsystem for "remember me"	Client Subsystem
Structs and enums (FRedwood*, ERedwood*)	Types		Types
URedwoodClientChatSubsystem, URedwoodChatSettings	Subsystem / settings	Clients	Optional Plugins
URedwoodSteamClientInterface	Static helpers + async node	Clients	Optional Plugins
URedwoodEOSClientInterface	Static helpers + async node	Clients	Optional Plugins
URedwoodAbilitySystemComponent	Ability system component	Your pawn or player state	Optional Plugins
USIOJsonObject, USIOJsonValue, USIOJLibrary	JSON helpers	Anywhere	Optional Plugins

Renamed classes

If you're upgrading an older project, you may see old names in your assets. DefaultRedwoodCore.ini contains [CoreRedirects] so these load correctly: for example RedwoodTitleInterface is now RedwoodClientInterface, RedwoodTitleGameSubsystem is now RedwoodClientGameSubsystem, RedwoodGameSubsystem is now RedwoodServerGameSubsystem, RedwoodPersistenceComponent is now RedwoodSyncComponent, and RedwoodPersistentItemAsset is now RedwoodSyncItemAsset. "Server" in older function and struct names generally became "Proxy" (e.g. CreateServer is now CreateProxy).