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The NPC Builder Unreal plugin adds asynchronous Blueprint nodes so you can chat with AI‑powered NPCs without leaving the editor.
It supports Unreal Engine 5.0 and higher.

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Prerequisites

  • Unreal Engine 5.0+
  • NPC Builder account with an active plan
  • Client ID / Secret (or Bearer token) generated in Developers → API Keys

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1 · Install the plugin

1

Download

Get NPCBuilder.unrealplugin from the Unreal Marketplace (or company download link).
2

Enable in project

Copy the plugin into your project’s Plugins/ folder  →  restart the editor.
Then open Edit → Plugins and ensure NPC Builder SDK is ticked.

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2 · Configure credentials

Add credentials to Config/DefaultGame.ini: 
[/Script/NPCBuilderSDK.NPCBuilderSDKSettings]
ClientId=YOUR_CLIENT_ID
ClientSecret=YOUR_CLIENT_SECRET
GameId=YOUR_GAME_ID
BearerToken=YOUR_BEARER_TOKEN ; optional

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3 · Blueprint workflow

1

Create Session

Use the Create Session node to obtain Session ID.
Provide ClientId/ClientSecret pins only if not set in DefaultGame.ini.
2

Update Character

Pass the Character ID (from the dashboard) and change optional fields (model, tone, events).
3

NPC Interaction

Send player text; the node returns response plus character_events.
Use the response pin to update UI and parse events for gameplay.
4

Reset Conversation (optional)

Clear memory when the player leaves or you need a fresh start.

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4 · Handling events

Events defined on the platform appear in character_events or user_events arrays. 
Event OnNPCEvent
 ├── Branch  (EventName == "dance")
 └── Play Montage (NPCA_DanceMontage)
Each event can include a referenced item. Use the plugin’s delegate to fetch the mapped GameObject: 
npcInteractions->OnGetItemObject.AddDynamic(this, &AMyActor::HandleItem);
All plugin Blueprint nodes are asynchronous—network calls never block the game thread.
Need a REST example instead of Blueprints? See Interactions API guide.
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