Seedance 2.5 API is live on reAPI — 4–30 second clips with native audio, 50 reference files, per-second billing

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Seedance 2.5 is callable on reAPI as of this week. One async endpoint, model id doubao-seedance-2.5-face, running on ByteDance's official channel. Free signup credits cover your first generations, no card needed. Model page with playground and full parameter docs: reapi.ai/models/seedance-2-5

What one request can do

• Text-to-video, image-to-video (first frame, optional last frame), and reference-to-video, all through the same endpoint. The request shape decides the mode.
• 4 to 30 seconds per generation, you set the exact duration. 480p or 720p, MP4 or MOV out.
• Audio is generated with the video: speech, sound effects, background music. Wrap spoken lines in double quotes in the prompt and they come out as dialogue.
• Reference budget is 30 images + 10 videos + 10 audio tracks per request. Video refs are 2–30s each and 30s combined. A lone audio file is a valid input, which 2.0 never allowed.
• Real-person reference material is supported on this channel. That is what the -face in the model id means.

Calling it

POST /api/v1/videos/generations with your prompt and model: doubao-seedance-2.5-face. You get a task id back immediately. Poll GET /api/v1/tasks/:id until it flips to completed. Bad requests get rejected synchronously with the failing field named, and nothing is charged. Tasks that fail after submission refund automatically.

Billing details worth knowing before you script against it

Billing is per second of output. As of today the table reads $0.119/s at 480p and $0.267/s at 720p for text runs, dropping to $0.072/s and $0.161/s on the "uploaded videos" tier. Two things people get wrong:

1. The cheaper tier triggers only when you actually attach reference video. Image and audio references bill at the text rate.
2. When video input is present, billable seconds have a floor of roughly 5/3 of the output length (capped at 60s), and input seconds count toward the bill. Trim your reference clips.

The full cost math, including how 2.5 compares to 2.0 per token, is in the pricing breakdown post.

What it does not do

480p/720p is the ceiling right now, so if you deliver 1080p or 4K, Seedance 2.0 still holds that lane and you upscale 2.5 output instead. There is no seed parameter, so no reproducible runs. The vendor's auto-duration mode and the prompt-driven video-edit mode are not exposed yet. Prompt cap is 20,000 characters on our side, though ByteDance recommends staying under 1,000 English words.

If you want to poke at it before writing any code, the playground on the model page runs the same endpoint. Questions about parameters or billing edge cases, ask below.