What is an AI Avatar?

Quick overview of how AI Avatars work in ACE AI Spark — the Replica (face + voice), the Persona (brain), and what you can do with one.

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An AI Avatar is a realistic, talking version of a person — yours or one of our stock avatars — that can have live conversations with anyone you share it with, or appear in AI-generated videos. This page explains the pieces, what each one does, and what you need to set up.

The two pieces of every avatar

Every avatar you create is made up of two things working together:

The Replica — the face and the voice. This is the part that looks and sounds like a real person. You either pick one of our ready-made stock avatars or upload a short training video of yourself to create your own. The Persona — the brain. The same face can be wrapped in many different personas. A "Sales Persona" greets visitors and answers product questions. A "Tutor Persona" patiently explains a topic. The persona decides how your avatar behaves and what it knows. Think of it like an actor (the Replica) reading from a script (the Persona). You can swap the script without swapping the actor.

What you can do with an avatar

Generate videos from a script — perfect for product walkthroughs, course modules, social posts.
Share a live conversation link — anyone who opens the link talks face-to-face with your avatar. No signup needed for the visitor.
Embed it on your website — drop the floating-button widget on any page so visitors can chat with your avatar without leaving your site.

The fields you'll see when building a persona

When you open the persona builder you'll see a handful of fields. Each one has a (?) icon next to it for a quick refresher, and most have a deeper guide too. The short version:

Persona name — your label, only visible to you.
Avatar (face) — which Replica this persona uses.
System prompt — the most important field. Describes who the avatar is, how it talks, what it covers. Read the System Prompt guide →
Opening greeting — the first line the avatar speaks when someone starts a session.
Language — the language the avatar speaks. Multilingual options exist for mixed-language audiences.
Intelligence model — the brain behind the responses. Pick based on whether you care more about speed or depth.
Pronunciation dictionary — optional list of tricky words (brand names, foreign terms) and how to pronounce them.
Objectives — optional structured goals like "qualify the lead" or "collect an email".
Guardrails — optional rules like "no medical advice" or "never quote prices".
Knowledge Base — optional documents the avatar can draw on during conversation.

How long does setup take?

Picking a stock avatar and writing a basic persona takes about 5 minutes. Training your own avatar from a video adds 30–60 minutes of processing time. Once you have one ready, every new persona on top of it takes another 2–5 minutes.

You don't need to fill in everything. The minimum to create a working persona is: a name, a face (Replica), and a system prompt. Everything else is optional and can be added later.

Where to go next

Writing a great System Prompt — the field that makes the biggest difference.
Open AI Avatars to start building.