> ## Documentation Index > Fetch the complete documentation index at: https://docs.npcbuilder.com/llms.txt > Use this file to discover all available pages before exploring further. # Introduction > Welcome to the NPC Builder documentation NPC Builder brings AI-driven, context-aware NPCs to your games.\ Use these guides to set up your account, integrate our SDKs, and call the APIs. Active plan required: API and SDK access require an NPC Builder subscription.\ View plans & pricing. ## Get started Sign up, generate a token, and receive your first NPC reply in minutes. Learn about all the entities existing in NPC Builder and how to use them. ## Game-engine integrations Unity plugin – light background Unity plugin – dark background Import the package, add credentials, and chat with NPCs using C# events. Unity plugin – light background Unity plugin – dark background Blueprint nodes for asynchronous conversations in Unreal Engine 5. ## API guides Authenticate, send messages to NPCs, and handle events in responses. Programmatically manage Games, Worlds, Regions, Locations, and Characters. Need full endpoint details? Explore the OpenAPI reference.