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POST
/
v1
/
images
/
generations
curl -s https://api.cometapi.com/v1/images/generations \
  -H "Authorization: Bearer $COMETAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "doubao-seedream-5-0-260128",
    "prompt": "a cat wearing a scarf sitting by the window watching rain, illustration style",
    "size": "2K",
    "response_format": "url",
    "watermark": false
  }' | jq -r '.data[].url'
{
  "created": 123,
  "data": [
    {
      "url": "<string>",
      "b64_json": "<string>",
      "size": "<string>"
    }
  ],
  "usage": {
    "generated_images": 123,
    "output_tokens": 123,
    "total_tokens": 123
  },
  "model": "<string>"
}

​
Overview

Generate images using ByteDance’s Seedream models through the standard OpenAI-compatible /v1/images/generations endpoint. Supports both text-to-image and image-to-image generation. For the full model list, see the Models page. For detailed parameter documentation from the provider, see the VolcEngine documentation.
When using sequential (multi-image) generation, set sequential_image_generation to auto and optionally configure sequential_image_generation_options.max_images to limit the number of output images. The total number of reference images plus generated images must be ≤ 15.

​
Image-to-image

Pass one or more reference images via the image parameter (array of URLs or base64 data URIs) along with a text prompt. Supports up to 14 reference images.

​
Returned URL gives AccessDenied?

The returned url is a signed object-storage link that contains & and other special characters.
If you copy the raw JSON and paste it directly into a browser or script, shell escaping or terminal truncation may strip the signature parameters, resulting in:
\{"Code":"AccessDenied","Message":"Access Denied","EC":"0003-00000015"\}
How to fix:
  • curl: pipe through | jq -r '.data[].url' to extract the URL cleanly.
  • Python: use result.data[0].url or image["url"] — the string is already complete; pass it directly to requests.get() or webbrowser.open().
  • JavaScript: same idea — result.data[0].url.
  • General: make sure & and % in the URL are not truncated or double-escaped.

Authorizations

​
Authorization
string
header
required

Bearer token authentication. Use your CometAPI key.

Body

application/json

Parameters for Seedream image generation (text-to-image and image-to-image).

​
model
string
default:doubao-seedream-5-0-260128
required

Model to use. See the Models page for current Seedream model IDs.

​
prompt
string
default:a cat wearing a scarf sitting by the window
required

Text prompt describing the image to generate. Supports both Chinese and English. Recommended max 300 Chinese characters or 1000 English characters.

​
response_format
enum<string>
default:url

Output format. url returns a temporary image link (valid for 24 hours); b64_json returns base64-encoded image data.

Available options:
url,
b64_json
​
size
string
default:2048x2048

Output resolution. Presets 2K, 4K, or exact pixels like 2048x2048, 2304x1728, 2848x1600, 1600x2848, etc. Default: 2048x2048.

​
image
string[]

Reference image(s) for image-to-image generation. Each item is a public URL or base64 data URI (data:image/png;base64,...). Supports up to 14 reference images. Supported formats: jpeg, png, webp, bmp, tiff, gif.

​
watermark
boolean
default:true

When true, adds an 'AI Generated' watermark to the bottom-right corner of the output image.

​
guidance_scale
number
default:2.5

Controls how closely the output follows the prompt. Higher values increase adherence but may reduce naturalness. Range: 1.0–10.0. Not supported by Seedream 5.0 (ignored).

​
seed
integer
default:-1

Random seed for reproducible outputs. Range: -1 to 2147483647. Use -1 (default) for random generation. Legacy parameter — ignored by newer models.

​
sequential_image_generation
enum<string>
default:disabled

Controls sequential (multi-image) generation mode.

  • auto: model decides whether to generate a sequence based on the prompt
  • disabled: always generate a single image
Available options:
auto,
disabled
​
sequential_image_generation_options
object

Configuration for sequential (multi-image) generation. Only effective when sequential_image_generation is auto.

​
output_format
enum<string>
default:jpeg

Output image file format. Options: png, jpeg.

Available options:
png,
jpeg

Response

200 - application/json

Successful Response

​
created
integer
required

Unix timestamp (seconds) when the image was generated.

​
data
object[]
required

Array of generated image objects.

​
usage
object
required

Resource usage information for this request.

​
model
string

The model used for generation.