# Seedream 5.5 API

Complete API reference for Seedream 5.5 models by ByteDance.

## Model Variants

This API supports two model variants:

| Model | ID | Description |
|-------|-----|-------------|
| **Seedream 5.5** | `seedream-v5.5` | High-quality text-to-image generation |
| **Seedream 5.5 Edit** | `seedream-v5.5-edit` | Image editing with reference images |

## Quick Comparison

| Feature | Seedream 5.5 | Seedream 5.5 Edit |
|---------|------------------|-----------------------|
| Input | Text prompt | Image(s) + Text prompt |
| Aspect Ratios | 8 options | 8 options |
| Resolutions | 1K, 1.5K, 2K | 1K, 1.5K, 2K |
| Image Input | No | Required (1-10 images) |

### Supported Aspect Ratios

`16:9`, `4:3`, `3:2`, `1:1`, `2:3`, `3:4`, `9:16`, `21:9`

## Seedream 5.5 (Text-to-Image)

### Endpoint

```
POST /api/v1/image/task
```

### Request Parameters

#### Required

| Parameter | Type | Description |
|-----------|------|-------------|
| `model_name` | string | Must be `"seedream-v5.5"` |
| `prompt` | string | Image generation prompt, up to 5000 characters |
| `resolution` | string | Output resolution: `"1k"`, `"1.5k"`, or `"2k"`; no default |
| `width` | integer | Width ratio value (e.g., 16 for 16:9); required with `height`; no default |
| `height` | integer | Height ratio value (e.g., 9 for 16:9); required with `width`; no default |

**Note:** The width:height ratio must be one of: `16:9`, `4:3`, `3:2`, `1:1`, `2:3`, `3:4`, `9:16`, `21:9`

#### Optional

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `background` | string | `"auto"` | Background mode: `"auto"` (automatic), `"transparent"`, or `"opaque"` |

### Example Request

```javascript
const response = await fetch('https://api.flaq.ai/api/v1/image/task', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    model_name: 'seedream-v5.5',
    prompt: 'Editorial fashion portrait, soft window light, muted palette',
    resolution: '1.5k',
    width: 16,
    height: 9,
    background: 'auto'
  })
});

const { data } = await response.json();
const taskId = data.task_id;
```

## Seedream 5.5 Edit (Image Editing)

### Endpoint

```
POST /api/v1/image/task
```

### Request Parameters

#### Required

| Parameter | Type | Description |
|-----------|------|-------------|
| `model_name` | string | Must be `"seedream-v5.5-edit"` |
| `prompt` | string | Description of desired edits, up to 5000 characters |
| `image_url_list` | string[] | Array of image URLs to edit (1-10 images); 80 credits per non-empty entry, including duplicate URLs |
| `resolution` | string | Output resolution: `"1k"`, `"1.5k"`, or `"2k"`; no default |
| `width` | integer | Width ratio value (e.g., 16 for 16:9); required with `height`; no default |
| `height` | integer | Height ratio value (e.g., 9 for 16:9); required with `width`; no default |

**Note:** The width:height ratio must be one of: `16:9`, `4:3`, `3:2`, `1:1`, `2:3`, `3:4`, `9:16`, `21:9`

#### Optional

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `background` | string | `"auto"` | Background mode: `"auto"` (automatic), `"transparent"`, or `"opaque"` |

### Example Request

```javascript
const response = await fetch('https://api.flaq.ai/api/v1/image/task', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    model_name: 'seedream-v5.5-edit',
    prompt: 'Change the hairstyle',
    image_url_list: [
      'https://img.bestimage.ai/test/2026/7/1/ad8e011a-3e9b-49f0-9397-282bf51e2e45_162640331.jpeg'
    ],
    resolution: '1.5k',
    width: 16,
    height: 9,
    background: 'auto'
  })
});

const { data } = await response.json();
const taskId = data.task_id;
```

### Single Image Edit Example

```javascript
{
  model_name: 'seedream-v5.5-edit',
  image_url_list: ['https://img.bestimage.ai/test/2026/7/1/ad8e011a-3e9b-49f0-9397-282bf51e2e45_162640331.jpeg'],
  prompt: 'Change the hairstyle',
  resolution: '1.5k',
  width: 16,
  height: 9,
  background: 'auto'
}
```

### Multi-Image Edit Example

```javascript
{
  model_name: 'seedream-v5.5-edit',
  image_url_list: [
    'https://example.com/image1.jpg',
    'https://example.com/image2.jpg'
  ],
  prompt: 'Blend these images into a cohesive composition',
  resolution: '1.5k',
  width: 16,
  height: 9,
  background: 'auto'
}
```

## Response Format

### Initial Response

```json
{
  "code": 0,
  "message": "success",
  "data": {
    "task_id": "0ca5f379-327b-4d49-ba19-e38782ceb2f0",
    "response_url": "https://api.flaq.ai/api/v1/image/0ca5f379-327b-4d49-ba19-e38782ceb2f0",
    "task_status": "submitted"
  }
}
```

### Polling Response

Poll `GET /api/v1/image/{task_id}` to check status:

```json
{
  "code": 0,
  "data": {
    "task_id": "{task_id}",
    "task_status": "succeed",
    "task_status_msg": null,
    "response_url": "https://api.flaq.ai/api/v1/image/{task_id}",
    "task_result": {
      "credit": 200,
      "images": [
        {
          "url": "https://example.com/generated-image.png"
        }
      ]
    }
  },
  "message": "success"
}
```

### Error Response

```json
{
  "code": 1201,
  "message": "[width, height] Invalid parameter (e.g. wrong key or value)",
  "data": null
}
```

### Status Values

- `submitted`: Task accepted
- `processing`: Image generation in progress
- `succeed`: Image generation completed
- `failed`: Image generation failed

## Processing Time

Poll until the task status is `succeed` or `failed`; a submitted or processing task may not contain image results yet.

## Best Practices

1. **Detailed Prompts**: More descriptive prompts yield better results
2. **Aspect Ratio**: Match the ratio to your target use case before generating
3. **Image Edit Quality**: For editing, use high-resolution, well-lit source images