Seedance 2.0 Fast API

About Seedance 2.0 Fast

ByteDance Seedance 2.0 Fast publishes endpoints - text-to-video, image-to-video, reference-to-video and video-extend - returning 4-to-15-second clips at 480p or 720p with audio in the same pass.

Call it with the model name bytedance/seedance-2.0-fast/text-to-video on POST /jobs/createTask, from 34 credits for a 5-second clip ($0.34). New accounts get 30 free credits to try it in the Playground first.

Introduction

Seedance 2.0 Fast text-to-video builds the whole frame from the prompt — subject, set, camera, light — and renders the soundtrack in the same pass. Nothing anchors the picture, so this is the endpoint for a shot that does not exist yet.

Seedance 2.0 Fast is the speed tier of ByteDance's Seedance 2.0 line. Its endpoints return 4 to 15 second clips at 480p or 720p, with audio generated alongside the picture.

Choose a Seedance 2.0 Fast mode by starting material

Key features

One field set, three sources

All three endpoints take the same core fields: prompt, duration_seconds from 4 to 15 (or -1 to let the model choose), resolution at 480p or 720p, aspect_ratio, generate_audio and seed. What changes is the source that anchors the picture: nothing, an opening frame, or a set of references. A request built for one mode moves to another by adding or removing that source.

Picture and sound in one pass

generate_audio is on by default and renders ambience, movement effects and voice locked to the frames. Switching it off does not lower the rate in this tier, so turn it off only for silent loops or for material you will score in post.

Adaptive framing by default

aspect_ratio defaults to adaptive: image-to-video keeps the proportions of the opening frame, reference-to-video follows the primary reference, and text-to-video lets the model pick the shape the prompt suggests. The six fixed ratios, 16:9, 9:16, 4:3, 3:4, 1:1 and 21:9, are there when a placement dictates the shape.

Request parameters

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

Each task is rounded up to whole credits, so one run at the lowest tier costs 34 credits for a 5-second clip ($0.34).

For an exact number before you run, send the same body to POST /jobs/quote.

Use cases

Vertical cuts for a social feed

Ask for 9:16 directly and write the shot as a phone would see it: handheld, daylight through a window, ambient noise left in. The example below is exactly that — five seconds of a bus window seat, generated from a prompt with no footage behind it.

Coverage nobody is going to shoot

With no image to follow, the prompt is the only source of subject, set, camera and light. That makes this the endpoint for establishing shots, cutaways and b-roll that would otherwise need a location and a crew.

The first shot of a longer sequence

There is no extend endpoint in this line. Generate the opening shot here, export its final frame, and send that frame to image-to-video as the start of the next shot; wardrobe, set and light carry over because they are baked into the frame.

Prompt guide & pro tips

Order the prompt like a shot list

Subject, action, camera, light, sound, one idea per sentence. The extra seconds of a longer duration_seconds are room to finish one action, not to fit a second idea in; longer pieces are built by chaining shots.

Know where Seedance's own filter sits

For a literal result, drive the beat from a first frame on image-to-video instead.

Adapt the included example

The published example uses aspect_ratio 9:16, duration_seconds 5, generate_audio true and resolution 720p.

The prompt asks for phone-camera realism rather than cinema, which is what sells it as a selfie. Keep that register and change the person, the place and the gesture.

Draft at 480p, compare with a fixed seed

Iterate at 480p while the wording is still moving, then raise resolution to 720p once for the take you keep. To see what a prompt edit actually changed, fix seed and hold every other field constant; it is a comparison tool, not a promise of frame-identical repeats.

API quick start

Call the Seedance 2.0 Fast API in three steps

1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
2. Send the request. POST /jobs/createTask with model bytedance/seedance-2.0-fast/text-to-video and an input object that follows the parameter table. The response returns a task ID straight away.
3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.

# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "bytedance/seedance-2.0-fast/text-to-video",
  "input": {
    "prompt": "A slow aerial shot drifting over a misty pine forest at sunrise",
    "aspect_ratio": "adaptive",
    "resolution": "720p",
    "duration_seconds": 5,
    "generate_audio": true
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

Seedance 2.0 Fast API questions

All Seedance models

Seedance 2.0 Mini has the same settings and is the cheapest tier; full Seedance 2.0 adds 1080p and 4K.

• Seedance 2.5 APIByteDance's newest: 30-second clips with native audioFrom 56 credits for a 5-second clip
• Seedance 2.0 Mini APILightweight Seedance for quick 720p drafts with soundFrom 9 credits for a 5-second clip
• Seedance 2.0 APICinematic clips up to 4K with native audioFrom 33 credits for a 5-second clip
• Seedance 2.0 Fast APIFaster Seedance 2.0 with sound at 720pFrom 17 credits for a 5-second clip
• Seedance 1.5 Pro APINative-audio clips with an optional locked cameraFrom 9 credits for a 5-second clip

Other video APIs

• MiniMax H3 APIExpressive clips with audio, up to 2KFrom 28 credits for a 5-second clip
• Kling 3.0 API4K clips, multi-shot cuts and motion controlFrom 51 credits for a 5-second clip
• Vidu Q4 Preview APIUp to 4K clips with sound and spoken dialogueFrom 34 credits for a 5-second clip
• Wan 3.0 APIUp to 30-second clips with synced audioFrom 34 credits for a 5-second clip
• Kling O3 APIKling’s unified model: create, animate, reference and edit up to 4KFrom 51 credits for a 5-second clip
• MiniMax H3 Max APIFast clips with ambience, effects and musicFrom 38 credits for a 5-second clip

More about Seedance 2.0 Fast

Try it

Seedance 2.0 Fast AI Video Generator onlineCreate videos with Seedance 2.0 Fast in PopNow

Docs

Seedance 2.0 Fast model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesImage to video guide for the PopNow APIWebhooks: get Seedance 2.0 Fast results without polling