bytedance/seedance-2.0-fast

Seedance 2.0 Fast — the same request shape as Seedance 2.0, quicker and cheaper per token, capped at 720p.

Between the base model and Mini.

Slug	`bytedance/seedance-2.0-fast`
Kind	video
Vendor	bytedance
Endpoint	`POST /v1/byteplus/contents/generations/tasks`

Charged per job from what the generator reports it rendered — your Logs show the exact figure for each one; see balance and billing.

Calling it

curl https://api.sociaro.com/v1/byteplus/contents/generations/tasks \
  -H "Authorization: Bearer $SOCIARO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
        "model": "bytedance/seedance-2.0-fast",
        "prompt": "a paper boat on a rain-soaked street",
        "resolution": "720p",
        "duration": 5
      }'

# then poll the job id it returns:
curl https://api.sociaro.com/v1/byteplus/contents/generations/tasks/JOB_ID \
  -H "Authorization: Bearer $SOCIARO_API_KEY"

Parameters

Seedance 2.0 Fast — quicker and cheaper, same request shape

Field	Type	Required	Default	Values	What it does
`content`	array	yes	—	parts, each with its own type and an optional role	This is the whole input. `{"type":"text","text":…}`, `{"type":"image_url","image_url":{"url":…},"role":"first_frame"\|"last_frame"\|"reference_image"}`, `{"type":"video_url",…,"role":"reference_video"}`, `{"type":"audio_url",…,"role":"reference_audio"}`. Every other model on this endpoint takes flat fields — these three do not.
`resolution`	string	no	720p	480p · 720p	A tier this model does not have is refused with a 400 naming the ones it does. The generator would ACCEPT it and silently render 720p, so the check is ours and it costs you nothing.
`duration`	integer	no	5	4–15, or -1	Seconds. `-1` lets the model pick the length that suits the inputs.
`ratio`	string	no	adaptive	21:9 · 16:9 · 4:3 · 1:1 · 3:4 · 9:16 · adaptive
`output_format`	string	no	mp4	mp4	`mov` exists on 2.5 alone.
`generate_audio`	boolean	no	—	true · false
`bitrate_mode`	string	no	the model's own	standard · high	Not in the vendor's public reference, but the generator honours it: `high` encodes at a higher bitrate than `standard` (in one 480p measurement about 4.6–6.9 Mbps against 1.2–1.9 Mbps), and the price is the same, because these models are metered per token. The default differs by model, so leave it out to take the model's own.
`return_last_frame`	boolean	no	false	true · false	Asks for the closing still beside the clip. It arrives as `last_frame_url`, on the same expiring /v1/media terms, at NO extra cost — useful as the `first_frame` of the next clip.
`watermark`	boolean	no	false here	true · false	The vendor defaults this on; we default it off.
`seed`	integer	no	random	—	Every Seedance model we serve accepts it. The same seed gives similar, not identical, results: the vendor says complete consistency is not guaranteed.

Anything not listed here is refused rather than ignored, so a typo fails loudly instead of quietly producing something else.

Worked example

curl https://api.sociaro.com/v1/spicy/generations \
  -H "Authorization: Bearer $SOCIARO_API_KEY" -H "Content-Type: application/json" \
  -d '{ "model": "bytedance/seedance-2.0-fast",
        "content": [{ "type": "text", "text": "a paper lantern drifting over still water" }],
        "resolution": "720p", "duration": 5 }'

Same request shape as Seedance 2.0, quicker and cheaper per token — between the base model and Mini. Use it when Mini is not quite enough and the base model is more than you need.

480p and 720p only. Ask for 1080p or 4K and you get a 400 naming the two you can have. That check is ours: the generator would accept the value, ignore it, hand you 720p and bill you for it.

Metered per token like the other two, with the same minimum cost on video-input jobs.

How a job runs

These routes are a pass-through: you send BytePlus's own body and get their own response back, with our additions beside it. Generation takes longer than a request should wait, so it goes in three moves — submit, poll, collect.

# 1. submit — the id comes back as `id`. There is NO `job_id` on THIS response
curl -sS https://api.sociaro.com/v1/byteplus/contents/generations/tasks \
  -H "Authorization: Bearer $SOCIARO_API_KEY" -H "Content-Type: application/json" \
  -d '{ "model": "…", "content": [ … ] }'
# -> { "id": "cgt-…" }

# 2. poll every 5-10 s
curl -sS https://api.sociaro.com/v1/byteplus/contents/generations/tasks/cgt-… \
  -H "Authorization: Bearer $SOCIARO_API_KEY"
# -> { "status": "running", … }
# -> { "status": "succeeded", "content": { "video_url": "<the vendor's own link>" },
#      "media_url": "https://api.sociaro.com/v1/media/<media_id>" }

# 3. collect — the opaque id IS the credential, no header needed
curl -sSL "https://api.sociaro.com/v1/media/<media_id>" -o out.mp4

Images use POST /v1/byteplus/images/async and its poll in the same shape, and the faster models also answer synchronously at POST /v1/byteplus/images/generations — one request, the picture in the response. A model whose render outlasts the gateway's ~2-minute ceiling is refused there by name, telling you to use the async route.

Reading the poll

Two differences will bite a client written against the poll-style routes. The SUBMIT returns id, not job_id — code reading job_id there gets nothing and cannot poll at all. And status is the VENDOR'S vocabulary: running, succeeded, failed — not processing, completed, failed. A check for completed on this route never becomes true, which reads as a job that never finishes rather than as an error.

The POLL response does carry job_id beside the vendor's id, as a convenience, and it returns the vendor's whole body — around twenty fields — rather than the five-field shape the other routes use. Gate on status rather than on the poll's HTTP code.

Prefer media_url over the vendor's raw link. Both are returned: content.video_url (or data[].url for images) is theirs, kept for compatibility and due to be removed once nobody reads it; media_url is ours. Ours points at our host, hides the vendor's storage, and expires. A second asset arrives on the same terms — return_last_frame gives content.last_frame_url with last_frame_media_url beside it.

Collecting the result

media_url is a capability: the opaque id is the credential, so no Authorization header is needed and anyone holding the link can fetch it. It expires within the hour — download rather than store the link.

Rules the gateway adds

Your key must be granted this model — 403 otherwise — and either spelling satisfies the grant: our catalogue id or the vendor's own native one.

Because this is a pass-through, unknown fields go to the generator rather than being refused here, and it is the generator that decides. The exception is resolution, which we check ourselves: an unsupported tier is silently ignored upstream, so you would ask for the higher one, be handed a lower one, and be charged. A tier we cannot price is refused at submit, before any money is spent, with a message naming the ones this model has.

Ranges and enums are the generator's own, so an out-of-range value comes back as its rejection, in its wording and with its numbers.