Seedance NT Series

The NT series provides four independent open models, using MoonNexAI API Key to create asynchronous video task. Supports MoonNexAI to harmonize common parameters and Volcengine-compatible compatible parameters; request shapes do not represent that all official high-level functions are open.

Models and Borders

Open Model	resolution	Target duration
seedance-2.0-nt	720P	Integer 4 - 15 seconds
seedance-2.0-nt-fast	720P	Integer 4 - 15 seconds
seedance-2.0-nt-mini	720P	4 seconds only
seedance-2.5-nt	720P	Integer 4 - 30 seconds

The default target duration is 4 seconds, and duration: -1 is not supported. The actual duration of the output file may contain coding-tail differences and should read the media message of the successful result.

Four models have validated single-person public network reference images, reference_image, 4 seconds, 720P, 16:9 and the closed audio combination, with 1280×720 output being successful. Person media assets must still meet content security requirements. Multigraph, video and audio reference, specific combinations and numerical ceilings should be confirmed according to current model capabilities, and not apply other Seedance series limitations.

media assets and aspect ratio

reference images mode uses reference_image, aspect ratio, optional 16:9, 9:16, 1:1, 21:9, 4:3, 3:4, default 16:9. reference images describes the person or the image content and does not require to be the first strict frame for the output video.

Strict first-frame mode uses first_frame. In this mode, seedance-2.5-nt preserves the input frame's aspect ratio. Set aspect_ratio: "adaptive" in common requests or ratio: "adaptive" in compatible requests, or omit the ratio. An explicit fixed ratio is rejected. Use reference_image when fixed 16:9 output is needed.

• first_frame and last_frame each; last frame must be submitted with first frame.
• first and last frames cannot be used with reference_image, reference_video or reference_audio.
• adaptive applies only to first/last-frame mode on seedance-2.5-nt.
• Audio references must be accompanied by pictures or videos and cannot be submitted separately.

The public network media assets URL must have direct access to media files anonymously and remain valid until task is completed; do not use the page address that requires login. The example.com address in the example below is a placeholder and needs to replace the straight chain of pictures you are entitled to use.

Calling with a public image URL is not asset ID authentication. The public NT asset-authentication and Asset:// workflow is not yet verified, so examples use public URLs. Do not reuse authenticated IDs from other model families. Only ready assets prepared for the selected model can resolve; failures return an error without falling back to a public URL.

MoonNexAI Unified Common Parameters

curl https://moonnexai.com/v1/videos \
  -H "Authorization: Bearer <MOONNEXAI_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.5-nt",
    "prompt": "参考图中的人物自然转头，保持人物外观一致，镜头稳定。",
    "references": [
      {
        "media_type": "image",
        "role": "reference_image",
        "url": "https://example.com/person-reference.jpg"
      }
    ],
    "size": "720p",
    "aspect_ratio": "16:9",
    "duration": 4,
    "generate_audio": false,
    "watermark": false
  }'

model can be replaced with any NT model in the table, and the same group of 4 seconds reference images parameters can be preserved. You can also create task with /v1/video/generations.

Official compatibility parameters

Both protocols use the same MoonNexAI public model name and API Key. One request selection is for a set of field, do not submit content[] and references[] simultaneously, or repeat prompt.

Uniform parameters	Official compatibility parameters
prompt	content[].type: "text" and text
references[].media_type: "image" and url	content[].type: "image_url" and image_url.url
references[].role	role for media lines
size: "720p"	resolution: "720p"
aspect_ratio	ratio
duration, generate_audio, watermark	Same name as field

curl https://moonnexai.com/api/v3/contents/generations/tasks \
  -H "Authorization: Bearer <MOONNEXAI_API_KEY>" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.5-nt",
    "content": [
      {
        "type": "text",
        "text": "参考图中的人物自然转头，保持人物外观一致，镜头稳定。"
      },
      {
        "type": "image_url",
        "image_url": { "url": "https://example.com/person-reference.jpg" },
        "role": "reference_image"
      }
    ],
    "resolution": "720p",
    "ratio": "16:9",
    "duration": 4,
    "generate_audio": false,
    "watermark": false
  }'

content[] can also be used in /v1/videos. NT access is requested using polling; callback, Cancel, Remix, Extension Video and other advanced features are not in the range of verified on this page.

Query and Results URL

Create success means task is accepted only. Saves the returned public id or task_id, using the same API Key polling:

curl https://moonnexai.com/v1/videos/{task_id} \
  -H "Authorization: Bearer <MOONNEXAI_API_KEY>"

Officially compatible access:

curl https://moonnexai.com/api/v3/contents/generations/tasks/{task_id} \
  -H "Authorization: Bearer <MOONNEXAI_API_KEY>"

Check status and error: Continue polling in queue or running first, and process errors when failed; video_url, url or response-compatible content.video_url is read only if the result is final and no error. The success cannot be judged by the existence of URLs alone.

A downloadable URL returned by a successful task can be used directly by the client. Preserve the full address and query parameters; do not reconstruct the host or path or remove signatures. URLs may expire, so download or archive promptly. See video queries for response fields.

Billing

The four models are based on a million-million video token, which is ultimately settled on task usage.total_tokens; the billing slot is used when reference video is included. Target duration is not fixed at a sub-price, nor does it mean that it is charged only in seconds.

Task creation may preauthorize quota, with the difference settled against actual token usage after completion. An asynchronous-task refund can be a preauthorization adjustment and does not by itself prove task failure. Check the terminal task state and complete billing record. A failed submission that creates no task is not charged.

The current unit price and the actual applicable price for account are based on the prices in MoonNexAI Console and Price description and API.

Relevant Pages

• Seedance-2 Video Overview
• Video Model Matrix
• Create Video Job
• Query Video Job