API do SeeDance 2.0 Fast

What is SeeDance 2.0 Fast?

SeeDance 2.0 Fast is the speed-optimized model in ByteDance's SeeDance 2.0 family, called on UnificAlly as bytedance/seedance-2.0-fast. It carries over the full 2.0 input set instead of trimming it: text-to-video, first-and-last-frame, and omni-reference with up to nine images, three videos, and three audio files in one call. Videos run 4 to 15 seconds at 480p or 720p, and synchronized audio is generated with the picture unless you turn it off.

That makes Fast the 2.0 model for volume work. Use it to test prompts, wire up reference placeholders, and render social cuts in bulk, then send the requests that matter to Pro when the final pass needs it.

Key features of SeeDance 2.0 Fast

What SeeDance 2.0 Fast is best for

• Prompt sweeps

  Run many short variations of one idea, keep the seeds of the good ones, and compare them before spending a Pro render.

• Reference wiring tests

  Check that @Image1, @Video1, and @Audio1 land where you expect in an omni-reference prompt before a long final render.

• Social video in bulk

  Render 9:16, 1:1, and 16:9 versions of the same idea for different placements by changing only the aspect ratio.

• First-and-last-frame reveals

  Give a start image and an end image and let the model fill the motion between them. Either frame alone also works.

• Video with sound in one call

  Ads, explainers, and short scenes that need audio come back as one file, with no separate sound pass.

SeeDance 2.0 Fast use cases

Batch 20 prompt variations for an ad concept at 720p, record each seed, and send the two best payloads to Pro unchanged. Turn a product shot and a packaging shot into a reveal with first-and-last-frame mode. Restyle a source video by passing it as @Video1 with a look image as @Image1 and a prompt that says what to change. Generate vertical and widescreen cuts of the same scene for a social calendar, with synchronized audio already in the file.

When to use SeeDance 2.0 Fast

Use Fast when you need many renders, quick turnaround, or audio-backed drafts at 480p or 720p. On UnificAlly, Fast bills $0.1212/sec at 720p, against $0.129/sec on SeeDance 2.0 Pro and $0.0875/sec on SeeDance 2.0 Mini. Pick Pro for hero shots, paid placements, and anything that needs 1080p or 4K. Pick Mini when cost per second matters most.

SeeDance 2.0 Fast API examples

Call SeeDance 2.0 Fast from any language by POSTing to /v1/tasks. Full parameter docs live at docs.unifically.com/models/video/bytedance/seedance-2.0-fast.

curl -X POST https://api.unifically.com/v1/tasks \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "bytedance/seedance-2.0-fast",
    "input": {
      "prompt": "A drone shot flying over a neon-lit cyberpunk city at night",
      "aspect_ratio": "16:9",
      "duration": 5,
      "resolution": "720p"
    }
  }'

Successful submission returns a task_id. Poll GET /v1/tasks/<task_id> or set a callback_url on the request to receive the finished result.