Muse Image API Reference

Generate Muse Image pictures from a prompt or up to 9 reference images in seven aspect ratios, one image per request, priced per image and delivered as a task.

Muse Image is the image model from Meta Superintelligence Labs. One request makes one image from a prompt, or from a prompt plus up to 9 reference images, in one of seven aspect ratios. Send the request, keep the returned task ID, and read the finished image from the task. Reference images go in as URLs.

Model IDs

Model ID	Inputs	Aspect ratios	Images per request
`muse-image`	text, 0–9 images	`1:1`, `16:9`, `9:16`, `4:3`, `3:4`, `3:2`, `2:3`	1

See the model page for current prices.

Quick example

curl https://api.seedrouter.ai/v1/images/generations \
  -H "Authorization: Bearer $SEEDROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "muse-image",
    "prompt": "A red ceramic mug on a white table, soft studio light, product photography. No text, no logos.",
    "aspect_ratio": "1:1"
  }'

Endpoint

POST https://api.seedrouter.ai/v1/images/generations

Header	Value
Authorization	`Bearer YOUR_API_KEY`
Content-Type	`application/json`

The response is a task ({"id": "task_...", "status": "processing"}), not the finished image. Poll GET /v1/tasks/{task_id} for the result. Keep API keys in server-side code. References go in the same request through image_urls; /v1/images/edits is not used for this model.

Parameters

Field	Type	Default	Notes
`model`	string	required	`muse-image`
`prompt`	string	required	Must not be empty after trimming. Required with references too.
`image_urls`	URL list	none	0–9 public image URLs, 11 MB in total. Without them the request is text to image.
`aspect_ratio`	enum	auto	`1:1`, `16:9`, `9:16`, `4:3`, `3:4`, `3:2` or `2:3`. Leave it out for auto: references set the shape; text only gives `1:1`. Do not send `"auto"`.
`size`	enum	none	Compatibility alias of `aspect_ratio`: one of the ratios above, or `auto`. Pixel sizes such as `1024x1024` are refused. When both are valid, `aspect_ratio` wins.
`n`	integer	`1`	Only `1`. Each request returns one image.

Fields outside this list are dropped before the request is forwarded; they never cause an error and never change the output. There is no resolution, seed, negative prompt, mask or output format setting. callback_url is not available; poll the task instead.

Reference images

Pass up to 9 images in image_urls and say in prompt what to keep and what to change. Muse Image uses them as references for a new picture; with aspect_ratio left out, the result follows their shape.

{
  "model": "muse-image",
  "prompt": "Keep this exact jacket; show it folded in a flat lay of hiking gear on pine boards, soft morning light.",
  "image_urls": ["https://example.com/jacket.png"],
  "aspect_ratio": "9:16"
}

Media inputs

Each reference is a public HTTP(S) URL. Base64 data URIs are not accepted: upload the file to your own storage and pass its URL. Use PNG, JPEG or WebP images; the original files must total 11 MB or less across all references. A set over that limit fails after acceptance and is not charged.

Pricing dimensions

Check the model pricing section for current rates. Muse Image has one price per image:

cost = price per image × 1

Text-only and reference requests, and every aspect ratio, cost the same. The amount reserved when the task is accepted is the amount charged. View final charges in your account usage history. Failed tasks are not charged.

Output schema

Submission returns the task:

{"id": "task_...", "model": "muse-image", "status": "processing", "created_at": 1789689600}

Get the task

GET https://api.seedrouter.ai/v1/tasks/{task_id}

Poll every 10–20 seconds until status is completed or failed. A network timeout while polling does not mean generation failed: keep the task ID and resume checking it. Do not create another task to check progress.

Completed task

{
  "id": "task_...",
  "model": "muse-image",
  "status": "completed",
  "created_at": 1789689600,
  "finished_at": 1789689680,
  "output": {
    "created": 0,
    "data": [
      { "url": "https://static.seedrouter.ai/media/tasks/task_example/0.webp" }
    ]
  }
}

The image is delivered as WebP, the model's own format; there is no output format setting. The model sets the pixel size. In our tests a text-only request came back at 1600 × 1600, 16:9 at 2048 × 1152, 3:4 at 1344 × 1792 and 9:16 at 1152 × 2048, about 50–180 seconds after submission.

Errors

Requests rejected before a task is created return an HTTP error with an error object and are not charged. A task that fails after acceptance returns HTTP 200 when queried, with status: "failed" and an error object.

See the shared error catalog for codes, HTTP statuses, and retry guidance.

{
  "id": "task_...",
  "model": "muse-image",
  "status": "failed",
  "error": {
    "code": 60001,
    "message": "The request was rejected by the content policy. Please revise the prompt or input images."
  }
}

If submission itself times out, check your tasks before submitting again: the first request may have been accepted.

Tips

Name the subject, setting, light and framing; Muse Image follows a specific brief closely.
With references, say exactly what must stay the same, such as the product's color or shape.
Leave aspect_ratio out to match a reference's shape; set it to crop for a channel.
Add no text, no logos to keep invented marks out.

Muse Image

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