API Reference

Complete reference for all PlayKit Unreal SDK classes and Blueprint nodes.

All client classes (UPlayKitChatClient, UPlayKitImageClient, etc.) are ActorComponents — add them to an Actor in the editor or via AddComponent. They are not created through factory functions. Results are delivered via Blueprint-assignable events, not callbacks.

UPlayKitBlueprintLibrary

Static utility functions accessible from any Blueprint or C++.

SDK State

Function	Returns	Description
`IsReady()`	`bool`	Check if SDK is configured and ready
`GetVersion()`	`FString`	Get current SDK version
`IsAuthenticated()`	`bool`	Check if a valid auth token is present
`GetAuthToken()`	`FString`	Get the current auth token
`GetGameId()`	`FString`	Get the configured Game ID
`GetBaseUrl()`	`FString`	Get the API base URL

NPC Setup

Function	Description
`SetupNPC(NPCClient, ModelName)`	Initialize a `UPlayKitNPCClient` component with the given model

UPlayKitChatClient

UActorComponent for text generation. Stateless — it does not manage conversation history. Add to an Actor; bind events before calling methods.

Events

Event	Payload	Description
`OnChatResponse`	`FPlayKitChatResponse`	Fired when a non-streaming response is complete
`OnStreamChunk`	`FString` Chunk	Fired for each streaming text chunk
`OnReasoningChunk`	`FString` Chunk	Fired for reasoning/thinking chunks
`OnStreamComplete`	`FString` FullText	Fired when streaming finishes
`OnError`	`FString` ErrorMessage	Fired on failure
`OnStructuredResponse`	`FString` JsonString	Fired when structured generation completes

Methods

Method	Description
`GenerateText(Prompt)`	Generate a response for a single prompt (uses `SystemPrompt` property)
`GenerateTextAdvanced(Config: FPlayKitChatConfig)`	Generate with full message history and settings
`GenerateTextStream(Prompt)`	Stream a response (fires `OnStreamChunk` + `OnStreamComplete`)
`GenerateTextStreamAdvanced(Config)`	Stream with full config
`GenerateStructured(Prompt, SchemaJson)`	Generate structured JSON output (fires `OnStructuredResponse`)
`CancelRequest()`	Cancel the in-flight request
`IsProcessing()`	Returns `bool` — whether a request is in flight

Configuration Properties

Property	Type	Default	Description
`ModelName`	`FString`	`"default-chat"`	Model to use
`Temperature`	`float`	`0.7`	Response randomness (0.0–2.0)
`MaxTokens`	`int32`	`0`	Max tokens (0 = model default)
`SystemPrompt`	`FString`	—	System instruction for `GenerateText` shortcuts

C++ Example

// In Actor header:
UPROPERTY(VisibleAnywhere)
UPlayKitChatClient* ChatClient;

// In BeginPlay:
ChatClient->OnChatResponse.AddDynamic(this, &AMyActor::HandleResponse);
ChatClient->GenerateText(TEXT("Hello, who are you?"));

void AMyActor::HandleResponse(const FPlayKitChatResponse& Response)
{
    if (Response.bSuccess)
        UE_LOG(LogTemp, Log, TEXT("AI: %s"), *Response.Content);
    else
        UE_LOG(LogTemp, Error, TEXT("Error: %s"), *Response.ErrorMessage);
}

UPlayKitImageClient

UActorComponent for AI image generation. Results are delivered as FPlayKitGeneratedImage (Base64 PNG). Use Base64ToTexture2D to convert for engine use.

Events

Event	Payload	Description
`OnImageGenerated`	`FPlayKitGeneratedImage`	Fired when a single image is ready
`OnImagesGenerated`	`TArray<FPlayKitGeneratedImage>`	Fired when a batch is ready
`OnError`	`FString` ErrorMessage	Fired on failure

Methods

Method	Description
`GenerateImage(Prompt)`	Generate one image
`GenerateImageWithSeed(Prompt, Seed)`	Generate with a fixed seed for reproducibility
`GenerateImagesAdvanced(Prompt, Options: FPlayKitImageOptions)`	Generate with full options (count, size, seed, transparency)
`CancelRequest()`	Cancel the in-flight request
`IsProcessing()`	Returns `bool`
`static Base64ToTexture2D(Base64Data)`	Convert Base64 string to `UTexture2D*`

Configuration Properties

Property	Type	Default	Description
`ModelName`	`FString`	`"default-image"`	Model to use
`ImageSize`	`FString`	`"1024x1024"`	Default size string
`Quality`	`FString`	`"standard"`	`"standard"` or `"hd"`
`ImageCount`	`int32`	`1`	Default batch count (1–10)
`Seed`	`int32`	`-1`	`-1` = random

Supported Size Strings

"256x256", "512x512", "1024x1024", "1792x1024", "1024x1792"

C++ Example

ImageClient->OnImageGenerated.AddDynamic(this, &AMyActor::HandleImage);
ImageClient->GenerateImage(TEXT("A dragon flying over mountains"));

void AMyActor::HandleImage(const FPlayKitGeneratedImage& Image)
{
    if (Image.bSuccess)
    {
        UTexture2D* Texture = UPlayKitImageClient::Base64ToTexture2D(Image.ImageBase64);
        MyMesh->GetMaterial(0)->SetTextureParameterValue(TEXT("Base"), Texture);
    }
}

UPlayKitSTTClient

UActorComponent for transcribing audio files or raw audio data. For real-time microphone recording, use UPlayKitSTTComponent.

Events

Event	Payload	Description
`OnTranscriptionComplete`	`FPlayKitTranscriptionResult`	Fired when transcription succeeds
`OnError`	`FString` ErrorMessage	Fired on failure

Methods

Method	Description
`TranscribeFile(FilePath)`	Transcribe a local audio file
`TranscribeFileWithLanguage(FilePath, Language)`	Transcribe with explicit language hint
`TranscribeAudioData(AudioData, FileName)`	Transcribe raw PCM bytes
`SetModelName(ModelName)`	Change the transcription model
`SetLanguage(Language)`	Set default language code (e.g. `"en"`, `"zh"`)
`CancelRequest()`	Cancel in-flight request
`IsProcessing()`	Returns `bool`

UPlayKitSTTComponent

UActorComponent for real-time microphone recording and transcription. Pairs StartRecording/StopRecording with automatic transcription dispatch.

Events

Event	Payload	Description
`OnPlayKitTranscriptionResponded`	`FPlayKitTranscriptionResult`	Fired when transcription is ready
`OnPlayKitTranscriptionError`	`FString` ErrorMessage	Fired on failure

Methods

Method	Description
`StartRecording()`	Begin microphone capture
`StopRecording()`	Stop capture (transcription starts automatically)
`StartTranscription(Request: FPlayKitTranscriptionRequest)`	Transcribe with explicit options
`StartTranscriptionSimple()`	Transcribe the last recording with default settings
`GetLastSavedFilePath()`	Returns the path of the last saved recording

Configuration Properties

Property	Type	Description
`ModelName`	`FString`	Transcription model to use

UPlayKit3DClient

UActorComponent for text-to-3D generation. Generation is asynchronous; the SDK polls the task until completion.

Events

Event	Payload	Description
`OnCompleted`	`FPlayKit3DTask`	Fired when the 3D model is ready
`OnProgress`	`int32` Percent	Fired during generation with progress (0–100)
`OnStatusChanged`	`EPlayKit3DTaskStatus`	Fired when task status changes
`OnError`	`FString` ErrorMessage	Fired on failure

Methods

Method	Description
`Generate3D(Prompt)`	Generate a 3D model from a text prompt
`Generate3DWithNegative(Prompt, NegativePrompt)`	Generate with negative guidance
`Generate3DAdvanced(Config: FPlayKit3DConfig)`	Full configuration
`CancelTask()`	Cancel the current task
`QueryTaskStatus(TaskId)`	Poll a task by ID
`IsProcessing()`	Returns `bool`
`GetCurrentTaskId()`	Returns `FString`
`GetCurrentStatus()`	Returns `EPlayKit3DTaskStatus`
`GetCurrentProgress()`	Returns `int32` (0–100)

Configuration Properties

Property	Type	Default	Description
`ModelName`	`FString`	`"default-3d-model"`	Model to use
`ModelVersion`	`FString`	`"v2.5-20250123"`	Version string
`DefaultTextureQuality`	`EPlayKit3DQuality`	`Standard`	`Standard` or `Detailed`
`DefaultGeometryQuality`	`EPlayKit3DQuality`	`Standard`	—
`bDefaultPBR`	`bool`	`true`	Generate PBR materials
`DefaultFaceLimit`	`int32`	`50000`	Max polygon count (0–200000)

UPlayKitNPCClient

UActorComponent for NPC conversations. Automatically manages conversation history, memory, and reply predictions. Initialize via UPlayKitBlueprintLibrary::SetupNPC.

Events

Event	Payload	Description
`OnResponse`	`FString` Text	Fired when NPC reply is ready
`OnStreamChunk`	`FString` Chunk	Fired for each streaming chunk
`OnStreamComplete`	`FString` FullText	Fired when streaming finishes
`OnActionTriggered`	`FNPCActionCallArgs`	Fired when NPC triggers a registered action
`OnReplyPredictionsGenerated`	`TArray<FString>`	Fired with suggested player responses
`OnError`	`FString` ErrorMessage	Fired on failure

Conversation Methods

Method	Description
`Talk(Message)`	Send a message; fires `OnResponse`
`TalkStream(Message)`	Send with streaming; fires `OnStreamChunk` + `OnStreamComplete`
`IsTalking()`	Returns `bool` — whether a request is in flight

Character & Memory

Method	Description
`SetCharacterDesign(Design)`	Set the NPC's personality system prompt
`GetCharacterDesign()`	Returns current character design
`SetMemory(Name, Content)`	Set a named memory entry
`GetMemory(Name)`	Get a named memory entry
`GetMemoryNames()`	Returns `TArray<FString>` of all memory names
`ClearMemories()`	Remove all memories

History Management

Method	Returns	Description
`GetHistory()`	`TArray<FNPCMessage>`	Get full conversation history
`GetHistoryLength()`	`int32`	Number of messages
`ClearHistory()`	—	Reset the conversation
`RevertHistory()`	`bool`	Undo the last exchange
`RevertChatMessages(Count)`	`int32`	Undo the last N messages
`AppendChatMessage(Role, Content)`	—	Manually append to history
`SaveHistory()`	`FString`	Serialize history to JSON
`LoadHistory(SaveData)`	`bool`	Load from JSON

Reply Predictions

Method	Description
`GenerateReplyPredictions(Count)`	Generate suggested player responses (fires `OnReplyPredictionsGenerated`)

Action Results

Method	Description
`ReportActionResult(CallId, Result)`	Report the result of a single action
`ReportActionResults(Results)`	Report results of multiple actions (`TMap<FString, FString>`)

Configuration Properties

Property	Type	Default	Description
`Temperature`	`float`	`0.7`	Response randomness (0.0–2.0)
`bAutoGenerateReplyPredictions`	`bool`	`false`	Auto-generate predictions after each reply
`PredictionCount`	`int32`	`3`	Number of predictions to generate (2–6)

UPlayKitPlayerClient

UGameInstanceSubsystem for player info and credits. Access via UPlayKitPlayerClient::Get(WorldContextObject) or UPlayKitBlueprintLibrary::GetPlayerClient(WorldContextObject).

Events

Event	Payload	Description
`OnPlayerInfoUpdated`	`FPlayKitPlayerInfo`	Fired when player info is refreshed
`OnPlayerTokenReceived`	`FString` Token	Fired when a new player token arrives
`OnDailyCreditsRefreshed`	`FPlayKitDailyCreditsResult`	Fired when daily credits are added
`OnError`	`FString` ErrorMessage	Fired on failure

Methods

Method	Returns	Description
`static Get(WorldContextObject)`	`UPlayKitPlayerClient*`	Get the subsystem instance
`HasValidToken()`	`bool`	Check if a player token is present
`GetCachedPlayerInfo()`	`FPlayKitPlayerInfo`	Get last-fetched player info
`GetCredits()`	`float`	Shorthand for cached credits
`GetNickname()`	`FString`	Shorthand for cached nickname
`GetPlayerInfo()`	—	Async fetch; fires `OnPlayerInfoUpdated`
`SetNickname(Nickname)`	—	Update the player's display name
`RefreshDailyCredits()`	—	Trigger a daily credit refresh
`ExchangeJWT(JWT)`	—	Exchange a backend JWT for a player token
`SetPlayerToken(Token)`	—	Set a token directly
`ClearPlayerToken()`	—	Remove the current token

UPlayKitDeviceAuthFlow

UObject for the player device authentication flow. Create via CreateDeviceAuthFlow(WorldContextObject).

Events

Event	Payload	Description
`OnAuthUrlReady`	`FString` URL	Fired when the auth URL is ready to display
`OnStatusChanged`	`EDeviceAuthStatus`	Fired on status transitions
`OnAuthSuccess`	`FDeviceAuthResult`	Fired when authentication succeeds
`OnAuthError`	`FString` ErrorMessage	Fired on failure

Methods

Method	Description
`static CreateDeviceAuthFlow(WorldContextObject)`	Create a new flow object
`StartAuthFlow(GameId, Scope)`	Begin the flow (`Scope` defaults to `"player:play"`)
`CancelAuthFlow()`	Cancel
`GetStatus()`	Returns `EDeviceAuthStatus`
`GetAuthUrl()`	Returns `FString` — the URL to show the player
`GetUserCode()`	Returns `FString` — the user code (if applicable)
`IsActive()`	Returns `bool`

Method	Description
`RegisterAction(Action, Handler)`	Register an action by `FNPCAction` + `FOnActionExecute` delegate
`RegisterActionBinding(Binding)`	Register via `FNPCActionBinding` (useful for Blueprint)
`UnregisterAction(ActionName)`	Remove an action
`GetEnabledActions()`	Returns `TArray<FNPCAction>`
`HasEnabledActions()`	Returns `bool`
`ExecuteAction(Args)`	Manually execute an action
`GetActionsAsJsonSchema()`	Returns actions as JSON schema string

UPlayKitNPCActionLibrary (Helper Functions)

Function	Description
`GetActionString(Args, ParamName)`	Extract a string parameter from action call args
`GetActionNumber(Args, ParamName)`	Extract a float parameter
`GetActionInt(Args, ParamName)`	Extract an int32 parameter
`GetActionBool(Args, ParamName)`	Extract a bool parameter
`ActionHasParam(Args, ParamName)`	Check if parameter exists
`CreateAction(Name, Description)`	Build a `FNPCAction`
`AddStringParameter(Action, Name, Desc, bRequired)`	Add a string parameter to an action
`AddNumberParameter(Action, Name, Desc, bRequired)`	Add a number parameter
`AddBoolParameter(Action, Name, Desc, bRequired)`	Add a bool parameter
`AddEnumParameter(Action, Name, Desc, Options, bRequired)`	Add an enum parameter

UPlayKitAIContextManager

UGameInstanceSubsystem that tracks global player context and manages NPC conversation compaction. Access via UPlayKitAIContextManager::Get(WorldContextObject).

Player Description

Method	Description
`SetPlayerDescription(Description)`	Set a global player context string injected into all NPC prompts
`GetPlayerDescription()`	Returns `FString`
`ClearPlayerDescription()`	Remove the player description

NPC Tracking & Compaction

Method	Description
`RegisterNPC(NPC)`	Track an NPC for auto-compaction
`UnregisterNPC(NPC)`	Stop tracking
`RecordConversation(NPC)`	Mark that a conversation occurred (resets idle timer)
`EnableAutoCompact(TimeoutSeconds, MinMessages)`	Enable automatic history summarization
`DisableAutoCompact()`	Disable
`IsEligibleForCompaction(NPC)`	Returns `bool`
`CompactConversation(NPC)`	Manually compact one NPC's history
`CompactAllEligible()`	Compact all eligible NPCs; returns `int32` count

Data Types

FPlayKitChatConfig

USTRUCT(BlueprintType)
struct FPlayKitChatConfig
{
    TArray<FPlayKitChatMessage> Messages;
    float Temperature;     // 0.0–2.0
    int32 MaxTokens;       // 0 = model default
    bool bEnableThinking;
    EPlayKitThinkingEffort ThinkingEffort; // Minimal, Low, Medium, High, Max
};

FPlayKitChatResponse

USTRUCT(BlueprintType)
struct FPlayKitChatResponse
{
    bool bSuccess;
    FString Content;
    FString FinishReason;
    TArray<FPlayKitToolCall> ToolCalls;
    FString ErrorMessage;
    int32 PromptTokens;
    int32 CompletionTokens;
    int32 TotalTokens;
    FString Reasoning;     // Populated when thinking is enabled
};

FPlayKitGeneratedImage

USTRUCT(BlueprintType)
struct FPlayKitGeneratedImage
{
    bool bSuccess;
    FString ImageBase64;   // Base64-encoded PNG — convert with Base64ToTexture2D
    FString OriginalPrompt;
    FString RevisedPrompt;
    FDateTime GeneratedAt;
    FString ErrorMessage;
};

FPlayKitImageOptions

USTRUCT(BlueprintType)
struct FPlayKitImageOptions
{
    FString Size;          // e.g. "1024x1024"
    int32 Count;           // 1–10
    int32 Seed;            // -1 = random
    bool bTransparent;
};

FPlayKitTranscriptionResult

USTRUCT(BlueprintType)
struct FPlayKitTranscriptionResult
{
    bool bSuccess;
    FString Text;
    FString Language;
    float DurationSeconds;
    TArray<FPlayKitTranscriptionSegment> Segments;
    FString ErrorMessage;
};

FPlayKitPlayerInfo

USTRUCT(BlueprintType)
struct FPlayKitPlayerInfo
{
    FString UserId;
    float Credits;
    FString Nickname;
};

FNPCMessage

USTRUCT(BlueprintType)
struct FNPCMessage
{
    FString Role;     // "system", "user", "assistant"
    FString Content;
};

UPlayKitSettings

Project settings at Edit > Project Settings > Plugins > PlayKit SDK.

Setting	Type	Description
`GameId`	`FString`	Application ID from the dashboard
`DefaultChatModel`	`FString`	Default model for `UPlayKitChatClient`
`DefaultImageModel`	`FString`	Default model for `UPlayKitImageClient`
`DefaultTranscriptionModel`	`FString`	Default model for STT
`Default3DModel`	`FString`	Default model for `UPlayKit3DClient`
`FastModel`	`FString`	Fast model used for context compaction
`bEnableAutoCompact`	`bool`	Enable auto-compaction globally
`AutoCompactTimeoutSeconds`	`float`	Idle time before compaction eligibility
`AutoCompactMinMessages`	`int32`	Minimum messages required for compaction
`bEnableDebugLogging`	`bool`	Enable SDK debug output

API Reference

On this page