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Flux1 AI API docs
Video generation

Seedance 2.0 Mini

Lower-cost Seedance video generation with per-second pricing and optional audio.

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-mini
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: 415. 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.

Use text, one first frame or a first/last-frame pair. The API supports 480p/720p and 4–15 whole seconds. Audio is optional at the same price. Multimodal references, automatic duration and custom callbacks are not accepted.

Resolution names are provider tiers, not exact pixel guarantees. A verified 4-second 480p request produced an 864×496 H.264 video lasting about 4.04 seconds. output.video.duration records the requested duration; the media file can differ slightly due to frame rounding.

Results are stored in Flux R2 and expire 30 days later. Download before expires_at; no email reminder is sent. Status or storage interruptions keep the request queued. A retry with the same Idempotency-Key does not generate or charge twice.

Provider contract: KIE Seedance 2 Mini.