ByteDance · Image API

Seedance 4.0

seedance-4-0

A dependable image generation route for everyday content and creative workflows.

POST/v1/images/generations

Output count1–15

Reference imagesUp to 14

Resolution tiers1K · 2K · 4K

Generation

Generate with Seedance 4.0

Use ImgRouter's unified request contract and this model ID. The example uses recommended defaults from the route's current parameter guide.

cURL

curl https://api.imgrouter.com/v1/images/generations \
  -H "Authorization: Bearer $IMGROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: seedance-4-0-generate-001" \
  -d '{
  "model": "seedance-4-0",
  "prompt": "Editorial product photograph, precise materials, soft studio light",
  "size": "1:1",
  "resolution": "2K",
  "n": 1
}'

Request body

modelstring · requiredUse seedance-4-0.

promptstring · requiredGeneration or editing instruction between 1 and 5,000 characters.

sizestringSupported values: auto, 1:1, 4:3, 3:4, 16:9, 9:16, 3:2, 2:3, 2:1, 1:2, 21:9, 9:21.

resolutionstringSupported values: 1K, 2K, 4K.

ninteger · 1–15Number of output images. Defaults to 1 and cannot exceed 15.

reference_imagesstring[] · max 14Public HTTPS source images. Send this field to the edit endpoint.

Controls

Supported options

Aspect ratio or size

auto1:14:33:416:99:163:22:32:11:221:99:21

Resolution

1K2K4K

Output format

url

Route notes

Supports generation, editing, and sequential image workflows.

The total number of references plus outputs cannot exceed fifteen.

Use auto with reference images when the source aspect ratio should be preserved.

Reference workflow

Edit with reference images

Send public HTTPS source images with the same core controls. This route accepts up to 14 reference images.

POST/v1/images/edits

cURL

curl https://api.imgrouter.com/v1/images/edits \
  -H "Authorization: Bearer $IMGROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: seedance-4-0-edit-001" \
  -d '{
  "model": "seedance-4-0",
  "prompt": "Preserve the subject and composition. Change the scene to soft blue hour.",
  "size": "1:1",
  "resolution": "2K",
  "n": 1,
  "reference_images": [
    "https://example.com/reference.jpg"
  ]
}'

Describe both the intended change and the details that must remain consistent. Stable source URLs produce the most reliable edit requests.

Response

Read the completed output

Successful requests return completed image URLs and a request ID. Store the assets you need permanently; routed output URLs may expire.

200 · application/json

{
  "id": "req_01K4…",
  "object": "image.generation",
  "created": 1787424152,
  "data": [
    { "url": "https://static.imgrouter.com/images/req_01K4.webp" }
  ],
  "usage": { "images": 1 }
}

Use GET /v1/requests/{request_id} for reconciliation and GET /v1/balance for the authenticated key's current Credit position.