Seedance 2.0 – Flux1 AI API

Generate 4–15 second videos from text, a first frame, or first and last frames.

POST/api/v1/generations

JSON requestAsynchronousOne video per request

Price is resolution rate × whole seconds. The example shows the total for its duration. Reference images do not add an extra charge. Check credits_refunded to confirm a refund; unresolved submissions may require review.

Jump to request examples ↓

Authorization

Authorizationstringrequired

Bearer fx1_live_… — send your API key in the request header. Requires administrator approval and a completed paid purchase; new generations also require enough credits.

Idempotency-Keystringoptional

Use one unique value per generation and reuse it with the same body on retries. Printable ASCII, no spaces. A different body with the same key returns 409.

Maximum length: 128 characters

Manage API keys ↗

Request body

modelstringrequired

Use this exact model ID in the top-level request body.

seedance-2

promptstringrequired

Video description, 3–2,000 characters after trimming.

Maximum length: 2,000 characters

first_frame_urlstringoptional

Optional public HTTPS image URL (JPEG, PNG or WebP). Omit for text-to-video. Maximum URL length 2,048 characters.

last_frame_urlstringoptional

Optional last-frame HTTPS image URL; requires first_frame_url. Reference video/audio and mixed reference modes are not accepted.

aspect_ratiostringoptional

Output width-to-height ratio.

Default: 16:9

16:94:31:13:49:1621:9

resolutionstringoptional

Resolution determines the per-second rate. 1080p/4K are not available through this API.

Default: 720p

480p720p

durationnumberoptional

Whole seconds, 4–15 inclusive. Cost is the per-second rate multiplied by this value. Automatic duration (-1) is not accepted.

Default: 5

Range: 4–15. See field description for allowed values.

generate_audiobooleanoptional

Generate audio with the video. Both audio settings use the same displayed rate.

Default: true

Response & next step

A successful submission returns 202 and a generation id. Poll GET /api/v1/generations/{id} every 2–3 seconds until the status is succeeded or failed.

Read the result URL from output.video.url. Download it before expires_at (30 days after storage). On failure, inspect error and credits_refunded.

Generation lifecycle →Error reference →

Build your request

360 credits / 5s video

ModeResolution

Examples only. Run on your server with your API key.

# Set FLUX1_IDEMPOTENCY_KEY once per generation; reuse it on retries.
curl --request POST 'https://flux1.ai/api/v1/generations' \
  --header "Authorization: Bearer $FLUX1_API_KEY" \
  --header 'Content-Type: application/json' \
  --header "Idempotency-Key: ${FLUX1_IDEMPOTENCY_KEY:?Set a unique key for this generation}" \
  --data '{
  "model": "seedance-2",
  "prompt": "A paper boat drifting across a quiet pond, slow tracking shot",
  "resolution": "720p",
  "duration": 5,
  "aspect_ratio": "16:9",
  "generate_audio": true
}'

202 · POST /api/v1/generations

{
  "id": "gen_example",
  "status": "queued",
  "model": "seedance-2",
  "media_type": "video",
  "credits": 360,
  "credits_refunded": false,
  "input": {
    "prompt": "A paper boat drifting across a quiet pond, slow tracking shot",
    "resolution": "720p",
    "duration": 5,
    "aspect_ratio": "16:9",
    "generate_audio": true
  },
  "output": null,
  "expires_at": null,
  "content_expired": false,
  "error": null,
  "created_at": "2026-09-07T08:00:00.000Z",
  "completed_at": null
}

Model notes

seedance-2 uses the Seedance 2.0 model. First-frame and first/last-frame modes use the same duration-based price as text-to-video. Audio is optional and does not change the price.
This API offers 480p and 720p only. Reference video/audio inputs, automatic duration, custom callbacks, 1080p and 4K are not accepted.
Resolution names are provider tiers; dimensions and media duration can be rounded by the provider. output.video.duration records requested seconds, not an independently measured file duration.
Results are stored in Flux R2 before success. Download the video before expires_at, 30 days after storage. No email reminder is sent.
A temporary polling or storage failure leaves the task queued for retry. An ambiguous submission never triggers another provider submission automatically; use the same Idempotency-Key and request ID when checking progress.

Provider contract: KIE Seedance 2.