# Seedance 2 UGC (ugc)

> Seedance 2 UGC makes an ad clip from a scene frame or from an ordered reference set on the fast Seedance tier. It runs at 480p and 720p.

Status: roasOS API v1.1. Catalog `model-catalog@2026-10-06.v5`, pricing `customer-pricing@2026-11-05.v15`. The endpoint `POST /v1/ugc/seedance-2` is live. `POST /v1/generations` has no `ugc` type, so this endpoint is the only path to this model.

## Endpoint
POST https://api.roasos.com/v1/ugc/seedance-2
Auth: Authorization: Bearer roasos_sk_… (scope api:write). Idempotency-Key required. quote_only / quote_id / webhook_url as in https://docs.roasos.com/llms.txt.

## 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
Unit: clip. Pricing key: `seedance-2`.

| request | credits |
|---|---|
| `4s_720p` | 12 |
| `10s_720p` | 30 |
| `15s_720p` | 44 |
| `4s_720p_no_audio` | 12 |

Credits come from the roasOS pricing table (`MODEL_COSTS`) through the catalog. No other field changes the price.

## Modes
- `standard`
- `reference`

The worker derives the mode from the media fields of the request.
Provider endpoints: `bytedance/seedance-2.0/fast/image-to-video` · `bytedance/seedance-2.0/fast/reference-to-video`.

## Request fields
| field | type | required | default | rule |
|---|---|---|---|---|
| `aspect_ratio` | enum | no | `9:16` | `9:16`, `1:1`, `3:4`, `4:3`, `16:9`, `21:9` |
| `avatar_id` | string | no | — | UUID; only in `reference` |
| `avatar_upload` | string | no | — | https URL; ≤ 4,096 characters; only in `reference` |
| `duration_seconds` | integer enum | no | `5` | `4`, `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15` |
| `generate_audio` | boolean | no | `true` | — |
| `product_id` | string | no | — | UUID; only in `reference` |
| `prompt_mode` | enum | no | — | `wrapped`, `exact` |
| `quote_id` | string | no | — | UUID |
| `quote_only` | boolean | no | `false` | — |
| `references` | string[] | no | — | ≤ 9 items; only in `reference` |
| `resolution` | enum | no | `720p` | `480p`, `720p` |
| `scene_id` | string | no | — | UUID; only in `standard` |
| `scene_image` | string | no | — | https URL; ≤ 4,096 characters; only in `standard` |
| `script` | string | yes | — | ≥ 1 character; ≤ 10,000 characters |
| `wait_timeout_seconds` | integer | no | `0` | 0–60 |
| `webhook_url` | string | no | — | https URL; ≤ 4,096 characters |

The schema is strict: a field that is not in this table returns `400 unsupported_option`. Field names are the roasOS role names, one name per role across every family.

## Media
- `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

| role | items | max size | content types | duration |
|---|---|---|---|---|
| `references` | ≤ 9 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |
| `scene_image` | ≤ 1 | 10 MB | `image/jpeg`, `image/png`, `image/webp` | — |

- Refused: `elements`, `product_images`, `reference_images`, `image_url`, `end_image_url`, `video_urls`, `video_url`, `audio_urls`, `audio_url`, `voice_id`. A refused role returns `400 unsupported_option`.
- Every URL must be an immutable object on `https://cdn.roasos.com/…` that your workspace owns; any other URL is `400 reference_media_not_workspace_owned`. Upload with `POST /v1/uploads` (direct POST of the bytes to `put_url`, or a `source_url` import), then use the returned CDN URL.

## 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
- `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`: values not exposed — `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
Result kind `ugc`. Always present: `url`.
```json
{ "data": { "id": "gen_…", "kind": "ugc", "model": "seedance-2", "status": "completed", "result": {"url":"https://cdn.roasos.com/workspaces/ws_01/result"} } }
```
Files live on `https://cdn.roasos.com` and are immutable; a result URL can be a media input to the next call. Poll `GET /v1/jobs/{id}/status` → `{ id, status, updated_at }`, then `GET /v1/jobs/{id}/result` (`409 run_not_completed` until the job is `completed`, `failed` or `canceled`). Statuses: `queued → processing → completed | failed | canceled`.

## Example
```bash
# 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 — the same body and the same Idempotency-Key, quote_id instead 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_…", "kind": "ugc", "model": "seedance-2", "status": "queued", "credits_reserved": 12, "links": { "status": "/v1/jobs/gen_…/status", "result": "/v1/jobs/gen_…/result" } } }

# 3. poll
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
https://docs.roasos.com/models/ugc/seedance-2 · https://api.roasos.com/v1/catalog/ugc/seedance-2 · bytedance/seedance-2.0/fast/image-to-video · bytedance/seedance-2.0/fast/reference-to-video