Seedance 2 UGC

Endpoint

POST https://api.roasos.com/v1/ugc/seedance-2

Send your API key as a bearer token. The key needs the scope api:write. Every paid request also needs an Idempotency-Key header.

The envelope fields quote_only, quote_id, webhook_url and wait_timeout_seconds behave the same on each model endpoint. Refer to Jobs and Quotes and credits.

Good at

A quick draft or a variant sweep. Native audio. Reference mode takes a saved person, a saved product and your own style references. Use /v1/ugc/seedance-2-pro when the cut must be 1080p or 4K.

Pricing

The unit is one clip. Pricing key: seedance-2.

The credits come from the roasOS pricing table. No other field changes the price. To get the exact price of your request, send it with quote_only: true first.

Modes

• standard
• reference

roasOS selects the mode from the media fields of your request. You do not send a mode.

Provider endpoints: bytedance/seedance-2.0/fast/image-to-video · bytedance/seedance-2.0/fast/reference-to-video.

Request fields

The schema is strict. A field that is not in this table gets 400 unsupported_option. The field names are the roasOS role names. One role has one name in every family.

Media

This endpoint accepts these media roles:

• avatar_id — identity; the saved character reference sheet, with a derived portrait only where the model requires a single face or source frame
• product_id — product; resolves to the product image list
• references — style and appearance references
• scene_id — first frame — a scene this workspace owns
• scene_image — first frame — a CDN image

Every other role is refused: elements, product_images, reference_images, image_url, end_image_url, video_urls, video_url, audio_urls, audio_url, voice_id. A refused role gets 400 unsupported_option.

Prompt

• Standard mode: the worker appends the UGC facts block ("Use the supplied first frame … The requested format is a UGC video ad; preserve the supplied script/action …") to the script.
• Reference mode: no facts block. Write no @Image tags yourself; the worker binds every reference.
• Write the words to be spoken in quotes: says exactly with warm energy: "…".
• Describe motion as physics: "Realistic hand movements, she lifts the jar to chest height."
• Anchor the hands to an object. A contact point holds hands and fabric better.
• Use a static camera for a talking head. Use one subject and one action for each clip.
• Do not write claims, camera moves or music that the product does not have.
• Seedance reads the ordered @ImageN tags. The worker writes them for you; do not write them yourself.

Not exposed

These catalog entries describe omitted inputs, pinned values and source constraints. They do not imply that the provider accepts every listed field.

• bitrate_mode — pinned to standard on every UGC request.
• aspect_ratio — pinned to auto.
• end_user_id — not accepted by this public endpoint.
• video_urls — not accepted by this public endpoint.
• references — these values are not available: BMP, TIFF, GIF, HEIC, HEIF.
• avatar_id — not accepted by this public endpoint.
• product_id — not accepted by this public endpoint.
• seed — pinned to output only.
• negative_prompt — not accepted by this public endpoint.
• audio_urls — not accepted by this public endpoint.
• end_image_url — not accepted by this public endpoint.

Result

The result kind is ugc. Always present: url.

{
  "data": {
    "id": "gen_…",
    "kind": "ugc",
    "model": "seedance-2",
    "status": "completed",
    "result": {
      "url": "https://cdn.roasos.com/workspaces/ws_01/result"
    }
  }
}

The files are immutable objects on https://cdn.roasos.com. A result URL is a valid media input for your next request.

Example

The three steps are always the same: quote, run, poll.

# 1. Quote. Nothing is spent.
curl -X POST https://api.roasos.com/v1/ugc/seedance-2 \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-seedance-2-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_only":true,"script":"Two drops, morning and night. That is the whole routine."}'
# 200 { "data": { "kind": "quote", "quote_id": "q_7Hk...", "credits": 12, "expires_at": "...",
#        "confirmation": { "model": "seedance-2", "example": "4s_720p" } } }

# 2. Run. Same body, same Idempotency-Key, quote_id in place of quote_only.
curl -X POST https://api.roasos.com/v1/ugc/seedance-2 \
  -H "Authorization: Bearer roasos_sk_live_..." \
  -H "Idempotency-Key: 0f1c9e2a-seedance-2-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_id":"q_7Hk...","script":"Two drops, morning and night. That is the whole routine."}'
# 201 { "data": { "id": "gen_...", "status": "queued", "credits_reserved": 12 } }

# 3. Poll, then read the result.
curl https://api.roasos.com/v1/jobs/gen_.../status -H "Authorization: Bearer roasos_sk_live_..."
curl https://api.roasos.com/v1/jobs/gen_.../result -H "Authorization: Bearer roasos_sk_live_..."

Today

The app route POST /api/generate/ugc-ads { sceneId | sceneImage, script, model: "seedance-2", async: true } sends the same request. Use this endpoint instead: it is live.

See also

• llms.txt for this model — the same facts as one plain-text file for an agent.
• GET https://api.roasos.com/v1/catalog/seedance-2 — the machine-readable form: enums, defaults, limits and prices. Refer to the API reference.
• Jobs — how to poll a job and read its result.
• Provider endpoints: bytedance/seedance-2.0/fast/image-to-video · bytedance/seedance-2.0/fast/reference-to-video.