Best AI NPC Tools for Unity in 2026

Unity is still where most AI NPC experiments start, and the options have changed a lot in two years. Inworld retired its Character Studio and moved Unity developers to a code-first Runtime SDK. Replica Studios shut down. NVIDIA put its on-device work into Unreal Engine plugins. ElevenLabs shipped an early Unity SDK for its voice agents. And voice APIs got good enough that some teams build everything themselves.

This guide compares the main AI NPC tools for Unity: what each one is, what it leaves for you to build, and what to check before you commit.

Unity AI NPC tools at a glance

Three ways to add AI NPCs in Unity

A complete character platform. You design characters in a tool, then call them from Unity through an SDK. Neocortex, Convai and Charisma.ai work this way. Voice, memory, session handling and character consistency are maintained for you, so it is the shortest route to a shipped feature. The trade-off is a monthly bill and a vendor relationship.

A local inference library. LLMUnity runs models offline inside your build. There is no per-message cost and no network dependency. The trade-off is that it is a library, not a character system: no voice, no editor, and you choose, ship and tune the models.

A raw model or voice API. OpenAI Realtime, ElevenLabs Agents and Inworld's Runtime give you models and voices. You get full control. The trade-off is that you write the audio client, the key-issuing backend, the character prompts, memory, guardrails and game integration yourself, and keep maintaining them after launch as models and prices change.

The AI NPC tools for Unity, one by one

Neocortex

Each character is a visual graph: personality, emotion, knowledge, world, intents and actions are nodes a designer can edit and test in the browser, where testing never uses credits. The Unity SDK targets Unity 6 and ships six sample scenes: text chat, audio chat, actions, interactables, group chat and usage gating. Replies carry an emotion tag and actions your game runs, characters can perceive tagged objects, and up to six characters can share one conversation on Pro and Team plans. Voice streams in and out, including in WebGL builds, with cloned or designed voices.

Convai

Convai centres on embodied avatars and simulations, with characters configured in a web dashboard. Its Unity SDK covers desktop, mobile, Meta Quest and WebGL. Pricing counts each character response against a monthly quota, with concurrency set per API key and caps on monthly active users. On-premise deployment is available to enterprise customers.

Inworld

Inworld retired Character Studio and points Unity developers to its Unity AI Runtime SDK, which needs Unity 2022.3 LTS or later and lists Windows, Mac, Android and iOS. A Character template gives you a starting point, and the rest of the character is built in code. Inworld bills against a dollar credit balance for TTS, speech-to-text and model usage, and its TTS supports instant voice cloning.

Charisma.ai

Charisma.ai builds characters around authored story graphs, played through Unity and Unreal SDKs or JavaScript packages. Usage is billed in credits sized in experience minutes, with custom enterprise pricing.

LLMUnity

An open-source Unity library under Apache-2.0, built on llama.cpp. It runs GGUF models offline on PC, mobile and VR, and its docs note that larger models typically will not run on mobile hardware.

Player2

Player2's Unity SDK, published under MIT, adds NPCs with text-to-speech and speech-to-text. Each player signs in through the Player2 app or a browser, and usage runs on the player's own Player2 account.

ElevenLabs Agents

ElevenLabs publishes an early-stage ElevenAgents SDK for Unity 6.3 LTS and later, with a WebGL bridge, and warns that its APIs may change. Agents are billed per conversation minute with language model costs passed through. It is built for voice agents, so game knowledge, actions and character design are yours to build.

OpenAI Realtime

OpenAI has no official Unity SDK for its realtime voice models. You connect over WebRTC or WebSocket, issue short-lived keys from your own backend, and pay per audio and text token.

NVIDIA ACE

NVIDIA's ACE Game Agent SDK, in beta, ships on-device speech recognition, small language models and text-to-speech as Unreal Engine 5 plugins for RTX PCs. There is no Unity plugin.

What to look for in a Unity AI NPC tool

• Unity version and platforms. Check that it supports your Unity version and your targets, especially WebGL, where Unity has no built-in microphone support.
• Who can edit characters. If only programmers can change a character, every dialogue tweak waits for an engineer.
• Gameplay hooks. Characters should be able to trigger actions and react to your scene, not only talk.
• Voice. Speech-to-text and text-to-speech built in, ideally streamed.
• Cost model. Per-message, per-minute and per-player pricing behave very differently once players start talking.
• Exit options. Can you prototype locally or self-host if you need to?

Your first hour with Neocortex in Unity

1. Create a free account and build one character in the browser editor.
2. Talk to it in the browser until it sounds right.
3. Install the Unity SDK in a Unity 6 project and import the samples from the Package Manager.
4. Open the text chat sample, set your API key in the Neocortex settings and paste your project ID on the Smart Agent component.
5. Press Play and talk to your character, then try the audio chat, actions and interactables scenes.
6. Add an action of your own in the editor and handle it in a script.

Related comparisons

• Inworld AI alternative
• Convai alternative
• LLMUnity vs Neocortex
• AI NPC tools with local AI support

The verdict for Unity teams

For most Unity teams shipping a game, a character platform beats building your own, and Neocortex is built specifically for that job. You get a visual editor your designers can use, an SDK with sample scenes for text, voice, actions, interactables and multi-character chat, voice cloning and design, WebGL microphone support, and a path to local models and self-hosting.

All competitor details were last checked in October 2026.

Frequently Asked Questions