Download an asset

October 12, 2026

Table of contents

  1. Request Headers
  2. Response headers
  3. Responses
  4. Model
  5. Examples
  6. Try It

Download a file by its assetId: an image or video Muse made, from a finished job’s result.assets[], or a file you uploaded with POST /assets. The response body is the file itself, streamed from the Muse workspace of the account that holds it on each request. No copy is kept at useapi.net.

The API never deletes files: they stay in the account’s Muse workspace. A file that is no longer there, for example because it was deleted in the muse.ai app, answers 404.

https://api.useapi.net/v1/muse/assets/assetId

  • assetId is URL-encoded in the path (it contains :), for example user%3A12345-email%3A6578616d706c6540676d61696c2e636f6d-image%3Ad62d3099…jpg.
Request Headers 
Authorization: Bearer {API token}
Response headers
  • Content-Type: the file’s type, for example image/webp for a generated image or video/mp4 for a video.
  • Content-Disposition: inline; filename="<file name>", the name of the file in the workspace.
  • Content-Length: when Muse sends the size.
Responses

  • 200 OK

    The raw file bytes (not JSON), for example:

    Content-Type: video/mp4
Content-Length: 3753558
Content-Disposition: inline; filename="media-generation-restored-portrait-animation-0-4322afa2-10d0-47b0-acc6-675a129aa78e.mp4"

  • 400 Bad Request

    The path value is not a Muse assetId.

    {
  "error": "Path parameter assetId (…) is not a valid Muse asset id (from POST /assets or a job result)",
  "code": 400
}

  • 401 Unauthorized

    Invalid API token.

    {
  "error": "useapi.net ⁝ Unauthorized",
  "code": 401
}

  • 403 Forbidden

    The assetId was issued to a different API token.

    {
  "error": "This asset id does not belong to this API token",
  "code": 403
}

  • 404 Not Found

    The file is no longer in the account’s Muse workspace, or the account that holds it is not added.

    {
  "error": "This file is no longer in the Muse workspace of account [email protected]",
  "code": 404
}

    {
  "error": "Account [email protected] (from the asset id) is not configured",
  "code": 404
}

  • 502 Bad Gateway

    Muse did not send the file. Retry shortly.

    {
  "error": "Muse did not send the file (…), please retry",
  "code": 502
}

  • 503 Service Unavailable

    Muse could not be reached. Retry shortly.

    {
  "error": "Could not connect to the Muse workspace of account [email protected] (…), please retry shortly",
  "code": 503
}

  • 596 Account Error

    The account needs your attention, and it is paused until you add it again. You receive an email when this happens. There are two causes.

    Meta asks for a security check on the account. Sign in once at muse.ai in a browser, complete the check, then add the account again with POST /accounts using the same email and password. The API keeps using its session, so no new sign-in is needed.

    {
  "error": "Account [email protected]: Meta asks for a security check on account [email protected] (\"This account must complete a security checkpoint on the web\"). Sign in once at https://muse.ai in a browser, complete the check, then add the account again with POST /accounts",
  "code": 596
}

    Or Muse refused to sign the account in again when its session needed renewing, most often because the password was changed. Add the account again with the current password.

    {
  "error": "Account [email protected]: Muse refused to sign in account [email protected] (…). Update its password with POST /accounts, or sign in at https://muse.ai to clear the block, then re-add it",
  "code": 596
}
Model

A successful response is the file itself (not JSON), with the headers listed above. Errors return:

{ // TypeScript, all fields are optional
  error: string
  code: number
}
Examples 
  • ASSETID="user:12345-email:6578616d706c6540676d61696c2e636f6d-video:media-generation-restored-portrait-animation-0-4322afa2-10d0-47b0-acc6-675a129aa78e.mp4"
curl -H "Authorization: Bearer …" \
     "https://api.useapi.net/v1/muse/assets/$(python3 -c "import urllib.parse,sys;print(urllib.parse.quote(sys.argv[1],safe=''))" "$ASSETID")" \
     --output video.mp4

  • const token = "API token";
const assetId = "assetId from a finished job or POST /assets";
const apiUrl = `https://api.useapi.net/v1/muse/assets/${encodeURIComponent(assetId)}`;
const response = await fetch(apiUrl, {
  headers: {
    "Authorization": `Bearer ${token}`,
  },
});
if (!response.ok)
  console.log("error", response.status, await response.json());
else {
  const file = await response.arrayBuffer();
  console.log("downloaded", file.byteLength, response.headers.get("content-type"));
}

  • import requests
from urllib.parse import quote
token = "API token"
assetId = "assetId from a finished job or POST /assets"
apiUrl = "https://api.useapi.net/v1/muse/assets/" + quote(assetId, safe="")
headers = {
    "Authorization" : f"Bearer {token}"
}
with requests.get(apiUrl, headers=headers, stream=True) as response:
    response.raise_for_status()
    with open("video.mp4", "wb") as f:
        for chunk in response.iter_content(chunk_size=1 << 20):
            f.write(chunk)
Try It

The form fetches the file with your token and shows the image or video inline.