# Compare models

URL: https://docs.bithuman.ai/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](https://docs.bithuman.ai/models/how-it-works#audio-in-frames-out)). 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](https://docs.bithuman.ai/models/avatar-file) (`.imx`).

## The models

- [Essence 2](https://docs.bithuman.ai/models/essence-2) (New, Hot): A photoreal person from one portrait, live. Highlights: Photoreal, up to 1080p; Sharp mouth and teeth; Made for always-on kiosks and displays. Runs on: iPhone & iPad, Mac, Android, Linux (no GPU), Browser, Your servers, Cloud, Offline.
- [Expression 2](https://docs.bithuman.ai/models/expression-2) (New, Hot): Any character from one portrait: stylized, animal, robot or human. Highlights: Cartoons, animals, robots and people; Motion generated live from the audio; One photo is enough. Runs on: iPhone & iPad, Mac, Android, Linux (no GPU), Browser, Your servers, Cloud, Offline.
- [Essence 1](https://docs.bithuman.ai/models/first-generation): First generation. A pre-built identity with its mouth matched to the audio in real time. Highlights: Renders on a CPU, no GPU needed; Lip-sync patched live over pre-rendered motion; Custom gestures. Runs on: Mac, Linux (no GPU), Browser, Your servers, Cloud, Offline.
- [Expression 1](https://docs.bithuman.ai/models/first-generation): First generation. Animates a face from a portrait at runtime. Highlights: No per-identity build step; Renders on bitHuman cloud GPUs at 512×512; Can animate a photo with no agent. Runs on: Cloud.

Essence 2 Max is available only to Enterprise customers; it is not offered on other plans.

Essence 1 and Expression 1 are the [first generation](https://docs.bithuman.ai/models/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`](https://docs.bithuman.ai/api/errors#model-errors) before anything is charged.

## Where each model runs

Each place links to the page that sets it up.

| Where | Essence 2 | Expression 2 | Essence 1 | Expression 1 |
|---|---|---|---|---|
| [iPhone and iPad](https://docs.bithuman.ai/platforms/ios) | Yes | Yes | — | — |
| [Mac](https://docs.bithuman.ai/platforms/macos) | Yes | Yes | Yes | — |
| [Android](https://docs.bithuman.ai/platforms/android) | Yes | Yes | — | — |
| [Linux, no GPU](https://docs.bithuman.ai/deploy/cpu) | Yes | Yes | Yes | — |
| [Browser (WebGPU)](https://docs.bithuman.ai/platforms/web) | Yes | Yes | Yes | — |
| [Your servers](https://docs.bithuman.ai/deploy/self-hosted) | Yes | Yes | Yes | — |
| [bitHuman cloud](https://docs.bithuman.ai/deploy/cloud) | Yes | Yes | Yes | Yes |
| [Fully offline](https://docs.bithuman.ai/deploy/offline) | Yes | Yes | Yes | — |

Fully offline is for Business and Enterprise clients, bought in the console or through sales ([Fully offline](https://docs.bithuman.ai/deploy/offline)).

Rendering on your own hardware, every place but the bitHuman cloud, bills at the self-hosted rate ([pricing](https://docs.bithuman.ai/pricing)). How fast each model renders on each device: [Performance](https://docs.bithuman.ai/performance).