# BytePlus Seedream

Invoke supports BytePlus’s **Seedream** image generation family through the BytePlus Ark API. Seedream is a strong fit for 2K/4K generations and multi-reference image composition.

## Getting an API Key

1. Open the [BytePlus Console](https://console.byteplus.com/) and sign in.
2. Enable the **Ark** (model serving) product.
3. Create an API key with access to the Seedream models you plan to use.

## Configuration

Add your key to `api_keys.yaml` in your Invoke root directory:

```
external_seedream_api_key: "your-seedream-api-key"

# Optional — change only if you need a different regional endpoint

external_seedream_base_url: "https://ark.ap-southeast.bytepluses.com"
```

Restart Invoke for the change to take effect.

## Available Models

| Model | Modes | Reference Images | Batch | Native Size |
| --- | --- | --- | --- | --- |
| **Seedream 5.0** | txt2img, img2img | up to 14 | up to 15 | 2K |
| **Seedream 5.0 Lite** | txt2img, img2img | up to 14 | up to 15 | 2K |
| **Seedream 4.5** | txt2img, img2img | up to 14 | up to 15 | 2K |
| **Seedream 4.0** | txt2img, img2img | up to 14 | up to 15 | 2K |

The 4.x / 5.x models are batch-capable and accept up to 14 reference images per request.

### Supported Aspect Ratios

All Seedream models share the same aspect ratio set: `1:1`, `2:3`, `3:2`, `3:4`, `4:3`, `9:16`, `16:9`, `21:9`, rendered at 2K.

## Provider-Specific Options

Seedream exposes two provider-specific toggles in the parameters panel:

- **Watermark** — When enabled, BytePlus adds a small watermark to the output. Off by default.
- **Optimize Prompt** — When enabled, BytePlus rewrites your prompt server-side for better generation quality. Useful for short prompts; disable if you want the exact wording preserved.

**Seed** and **guidance scale** are not accepted by the 4.x / 5.x family.

## Reference Images

4.x and 5.x Seedream models accept up to 14 reference images alongside the prompt. Invoke’s standard reference-image panel is used — drag images in, and they are forwarded as base64 PNGs to the API.

## Tips

1. For multi-image composition (e.g. character + product), Seedream 4.5 is a good default.
2. When running large batches (`num_images > 1` on 4.x / 5.x), Invoke uses the `sequential_image_generation` API flag — each image is returned as it completes.
3. Set `external_seedream_base_url` if you need to route through a region-specific Ark endpoint.