Seedance 2.0 Fast API

Seedance 2.0 Fast text-to-video builds the whole frame from the prompt — subject, set, camera, light — and renders the soundtrack in the same pass. Nothing anchors the picture, so this is the endpoint for a shot that does not exist yet.

Seedance 2.0 Fast is the speed tier of ByteDance's Seedance 2.0 line. Its endpoints return 4 to 15 second clips at 480p or 720p, with audio generated alongside the picture.

Choose a Seedance 2.0 Fast mode by starting material

One field set, three sources

All three endpoints take the same core fields: prompt, duration_seconds from 4 to 15 (or -1 to let the model choose), resolution at 480p or 720p, aspect_ratio, generate_audio and seed. What changes is the source that anchors the picture: nothing, an opening frame, or a set of references. A request built for one mode moves to another by adding or removing that source.

Picture and sound in one pass

generate_audio is on by default and renders ambience, movement effects and voice locked to the frames. Switching it off does not lower the rate in this tier, so turn it off only for silent loops or for material you will score in post.

Adaptive framing by default

aspect_ratio defaults to adaptive: image-to-video keeps the proportions of the opening frame, reference-to-video follows the primary reference, and text-to-video lets the model pick the shape the prompt suggests. The six fixed ratios, 16:9, 9:16, 4:3, 3:4, 1:1 and 21:9, are there when a placement dictates the shape.

Vertical cuts for a social feed

Ask for 9:16 directly and write the shot as a phone would see it: handheld, daylight through a window, ambient noise left in. The example below is exactly that — five seconds of a bus window seat, generated from a prompt with no footage behind it.

Coverage nobody is going to shoot

With no image to follow, the prompt is the only source of subject, set, camera and light. That makes this the endpoint for establishing shots, cutaways and b-roll that would otherwise need a location and a crew.

The first shot of a longer sequence

There is no extend endpoint in this line. Generate the opening shot here, export its final frame, and send that frame to image-to-video as the start of the next shot; wardrobe, set and light carry over because they are baked into the frame.

# Generate the idempotency key once; reuse it when retrying after a lost response.
export SPICY_IDEMPOTENCY_KEY="${SPICY_IDEMPOTENCY_KEY:-$(uuidgen)}"
curl -X POST https://api.spicyapi.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $SPICY_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $SPICY_IDEMPOTENCY_KEY" \
  -d '{
  "model": "bytedance/seedance-2.0-fast/text-to-video",
  "input": {
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "resolution": "720p",
    "aspect_ratio": "adaptive",
    "bitrate_mode": "standard",
    "generate_audio": true,
    "duration_seconds": 5
  }
}'

# Copy data.taskId from the response into TASK_ID, then poll the status.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.spicyapi.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $SPICY_API_KEY"

See the API reference for authentication, the complete schema, polling, and error handling.