Docs index: /llms.txt · every page as Markdown: add .md

‹ Models

Compare models

Essence 2 renders a photoreal person; Expression 2 renders any character.

A bitHuman model turns speech audio into a lip-synced talking video of your avatar, live (how it works). Pick by subject: a real person, Essence 2; anything else, Expression 2. The same agent works on every platform that runs its model; on your own hardware it renders from an avatar file (.imx).

The models

Essence 1 and Expression 1 are the first generation. They stay supported, and nothing changes for agents that use them.

Choosing a model

Pick the model from the subject:

  • A real person: Essence 2.
  • Anything else (a cartoon or stylized character, an animal, a robot, a creature, a whole generated scene): Expression 2.
  • Not sure: create with model: "auto". A real person routes to Essence 2, anything else to Expression 2.
  • On a phone, a Mac or in a browser: Essence 2 or Expression 2.
  • Maintaining a first-generation agent: keep it. Essence 1 runs on your own CPU; Expression 1 runs in the bitHuman cloud.

Every model except Expression 2 needs a clear, real human face; otherwise creation is refused with 422 MODEL_SUBJECT_MISMATCH before anything is charged.

Where each model runs

Each place links to the page that sets it up.

WhereEssence 2Expression 2Essence 1Expression 1
iPhone and iPadYes
Swift package, Essence2Kit (iOS 26)
Yes
Swift package, Expression2
——
MacYes
Swift package (macOS 26, M3 or newer), CLI, Python
Yes
Swift package (macOS 13), CLI, Python
Yes
CLI (run), Python
—
AndroidYes
essence2-android
Yes
expression2-android
——
Linux, no GPUYes
CLI, Python
Yes
CLI, Python
Yes
CLI (run), Python
—
Browser (WebGPU)Yes
render=local, for avatars that have a browser build
Yes
render=local
Yes
render=local
—
Your serversYes
CLI, Python, LiveKit plugin
Yes
CLI, Python, LiveKit plugin
Yes
CLI (run), Python
—
bitHuman cloudYes
web embed, REST API, LiveKit
Yes
web embed, REST API, LiveKit
Yes
web embed, REST API, LiveKit
Yes
web embed, REST API, LiveKit
Fully offlineNot yet
Coming later
Yes
Linux x86_64 (Business & Enterprise)
Yes
Linux x86_64 and ARM64, macOS on Apple silicon (Business & Enterprise)
—

Fully offline is for Business and Enterprise clients, bought in the Console or through sales (Fully offline).

Rendering on your own hardware, every place but the bitHuman cloud, bills at the self-hosted rate (pricing). How fast each model renders on each device: Performance.

This section moved: docs.bithuman.ai/build/create-avatar#how-creation-works

This section moved: docs.bithuman.ai/resources/renamed#retired-model-and-file-names

This section moved: docs.bithuman.ai/models#choosing-a-model