Name: Seedance 2.5 API: 30-Second AI Video with Native Audio
Brand: magicapi
SKU: api-magicapi-multimodal-video-generator-bytedance-seedance-2-5
Availability: InStock
Author: API Market

Shashank Agarwal

# 🎬 Multimodal Video and Audio Generator API (ByteDance Seedance 2.5)

## Overview
Seedance 2.5 is a video generation model from ByteDance. Its developer describes it as ByteDance's flagship multimodal video model, with native audio, native 30-second generation and large multimodal reference sets.

Send a text `prompt`, optionally with a first-frame `image`, a `last_frame_image`, or sets of reference images, videos and audio files. The model generates a video of up to 30 seconds at 480p or 720p, with synchronized audio by default. Each request returns the URL of one video.

## Features
- **Text-to-video**: generate a video from a `prompt` alone. The model works best with detailed, structured "production brief" style prompts.
- **Image-to-video**: use `image` as the first frame, and add `last_frame_image` for first/last-frame generation.
- **Reference images**: up to 30 `reference_images` for character consistency, style guidance and scene composition. Refer to them in the prompt as [Image1], [Image2] and so on.
- **Reference videos**: up to 10 `reference_videos` (combined at most 30 seconds) for motion transfer, style reference, editing and extension. Refer to them as [Video1], [Video2] and so on.
- **Reference audio and lip-sync**: up to 10 `reference_audios` (combined at most 30 seconds) for audio-driven generation and lip-sync. Requires at least one reference image or video. Refer to them as [Audio1], [Audio2] and so on.
- **Native audio**: `generate_audio` (default `true`) adds synchronized dialogue (put spoken lines in double quotes in the prompt), sound effects and background music.
- **Duration**: 1 to 30 seconds (default 5), or -1 to let the model pick the length.
- **Resolution and shape**: `480p` or `720p` (default); aspect ratios `16:9` (default), `4:3`, `1:1`, `3:4`, `9:16`, `21:9` or `adaptive`.
- **Output**: `mp4` (default) or `mov`, with an optional `watermark`.

## Use Cases
1. **Short ads and social clips**: generate scenes with sound from a written brief.
2. **Animating stills**: turn a product photo or illustration into a clip with `image`, or control start and end with `last_frame_image`.
3. **Consistent characters**: keep a character or style across clips with `reference_images`.
4. **Editing and extending footage**: change or continue an existing clip passed in `reference_videos`.
5. **Talking characters**: drive lip-sync from `reference_audios` together with a reference image or video.

## Visual Examples
### Example Input
Prompt: "a golden retriever puppy running across a green meadow toward the camera, slow motion, warm afternoon light"

Settings: `duration` 5, `resolution` `480p`, `seed` 42. All other fields were left at their defaults (`16:9`, audio on, `mp4`).

### Example Output
[Watch the example output](https://blog.api.market/wp-content/uploads/2026/10/seedance-2-5-output-s48cvtrk-api-market-1.mp4)

## Input Parameters
| Field | Type | Required | Default | Allowed values | Description |
| --- | --- | --- | --- | --- | --- |
| `prompt` | string | No | `""` |  | Text prompt for video generation. Optional when a media input (image, reference images, videos or audios) is supplied. Works best with detailed, structured "production brief" style prompts |
| `image` | string (URL) | No | none |  | First-frame image for image-to-video or first/last-frame generation. Cannot be combined with reference images, videos or audios |
| `last_frame_image` | string (URL) | No | none |  | Last-frame image. Requires a first-frame `image`. Cannot be combined with reference images, videos or audios |
| `reference_images` | array of strings (URLs) | No | `[]` | Up to 30 | Reference images for character consistency, style guidance and scene composition. Cannot be combined with first/last frame images. Refer to them in the prompt as [Image1], [Image2], etc. |
| `reference_videos` | array of strings (URLs) | No | `[]` | Up to 10, combined at most 30 s | Reference videos for motion transfer, style reference, editing and extension. Refer to them in the prompt as [Video1], [Video2], etc. |
| `reference_audios` | array of strings (URLs) | No | `[]` | Up to 10, combined at most 30 s | Reference audio files for audio-driven generation and lip-sync. Requires at least one reference image or video. Refer to them in the prompt as [Audio1], [Audio2], etc. |
| `duration` | integer | No | `5` | -1 to 30 | Video duration in seconds. -1 lets the model pick the best length. Editing mode requires -1 |
| `resolution` | string | No | `720p` | `480p`, `720p` | Video resolution |
| `aspect_ratio` | string | No | `16:9` | `16:9`, `4:3`, `1:1`, `3:4`, `9:16`, `21:9`, `adaptive` | Video aspect ratio. `adaptive` lets the model choose based on the inputs. First/last-frame, editing and extension modes require `adaptive` |
| `generate_audio` | boolean | No | `true` |  | Generate synchronized audio with the video, including dialogue (use double quotes in the prompt), sound effects and background music |
| `watermark` | boolean | No | `false` |  | Add a watermark to the generated video |
| `output_format` | string | No | `mp4` | `mp4`, `mov` | Output video container format |
| `seed` | integer | No | none |  | Random seed for reproducible generation. Reproducibility is not guaranteed |

## Pricing
- **Pay As You Go (PAYG) pricing**: you only pay for what you use.
- **Price**: $0.13 per API unit.
- **Billing is per second of output video**, billed on the requested `duration` (with `duration` -1, on the length of the returned video). The price per second depends on `resolution` and on whether `reference_videos` is non-empty:

| `resolution` | Without reference videos | With reference videos |
| --- | --- | --- |
| `480p` | $0.13 per second (1 unit) | $0.54431 per second (4.187 units) |
| `720p` (default) | $0.29237 per second (2.249 units) | $1.22356 per second (9.412 units) |

- When you omit `resolution` and `reference_videos`, the default `720p` without reference videos applies: $0.29237 per second.
- The units of a request (seconds x units per second) are rounded up to a whole unit. For example, 5 seconds at `720p` without reference videos is 11.245 units, rounded up to 12 units: $1.56.
- `generate_audio`, `watermark`, `aspect_ratio`, `output_format`, reference images and reference audio do not change the price.
- **Example cost**: the example request below (5 seconds, `480p`, no reference videos) is 5 units: $0.65.
- **Failed or cancelled predictions are not billed.**
- **GET requests to check prediction status** are free and don't count toward API unit usage.
- **No monthly subscription fee.**

## API Documentation

### Base URL
All API requests go to: `https://prod.api.market/api/v1/magicapi/multimodal-video-generator-bytedance-seedance-2-5`

### Authentication
Send your api.market API key in the `x-api-market-key` header:
```
x-api-market-key: YOUR_API_MARKET_KEY
```

### Asynchronous Processing
**IMPORTANT**: This API is asynchronous. The flow is:
1. Send a POST request to `/predictions`. A successful request returns **201 Created** with a prediction `id` and a `status` of `starting` or `processing`.
2. Poll GET `/predictions/{id}` with that ID.
3. Keep polling while `status` is `starting` or `processing`.
4. Stop when `status` is `succeeded` (read `output`), `failed` or `canceled` (read `error`).

Video generation takes minutes: the 5-second example took about 140 seconds. A polling interval of 5 seconds and an overall timeout of 1200 seconds (20 minutes) work well.

### Endpoints

#### Create a Prediction
```bash
curl -X POST "https://prod.api.market/api/v1/magicapi/multimodal-video-generator-bytedance-seedance-2-5/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "bytedance/seedance-2.5",
    "input": {
      "seed": 42,
      "prompt": "a golden retriever puppy running across a green meadow toward the camera, slow motion, warm afternoon light",
      "duration": 5,
      "resolution": "480p"
    }
  }'
```

Response (201 Created):
```json
{
  "id": "s48cvtrkcxrmt0d1ccktpkm8tc",
  "version": "bytedance/seedance-2.5",
  "status": "starting",
  "created_at": "2026-10-22T10:27:47.819Z"
}
```

#### Check Prediction Status
```bash
curl -X GET "https://prod.api.market/api/v1/magicapi/multimodal-video-generator-bytedance-seedance-2-5/predictions/{id}" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

Response when the prediction has finished (200 OK):
```json
{
  "id": "s48cvtrkcxrmt0d1ccktpkm8tc",
  "status": "succeeded",
  "output": "https://blog.api.market/wp-content/uploads/2026/10/seedance-2-5-output-s48cvtrk-api-market-1.mp4",
  "error": null,
  "created_at": "2026-10-22T10:27:47.819Z",
  "started_at": "2026-10-22T10:27:47.832Z",
  "completed_at": "2026-10-22T10:30:08.324Z"
}
```

`output` is a single URL string pointing to the generated video.

### Status Codes
- **201 Created**: prediction created (POST `/predictions`). This is the normal success response.
- **200 OK**: prediction details returned (GET `/predictions/{id}`).
- **400 Bad Request**: invalid input, for example a `duration` above 30 or a `resolution` that is not in the list.
- **401 Unauthorized**: missing or invalid API key.
- **404 Not Found**: no prediction with that ID.
- **429 Too Many Requests**: rate limit exceeded.
- **500 Internal Server Error** or **503 Service Unavailable**: temporary server problem; retry later.

## Rate Limits
All plans allow 10 requests per second. Requests above that return `429 Too Many Requests`; back off before retrying and honour any `Retry-After` header. Polling a prediction with GET is free but still counts toward the per-second limit, so poll every 1 to 5 seconds rather than in a tight loop.

## Error Handling
- Check the HTTP status code of every request and read the response body for the error message.
- A prediction can also end with `status` set to `failed`; the `error` field then explains why. Failed predictions are not billed.
- Retry 429, 500 and 503 responses with exponential backoff. Fix the input before retrying a 400.

## Implementation Guide
### Example Code

#### JavaScript
```javascript
const apiKey = "YOUR_API_MARKET_KEY";
const baseUrl = "https://prod.api.market/api/v1/magicapi/multimodal-video-generator-bytedance-seedance-2-5";

async function createAndWaitForPrediction(input) {
  const response = await fetch(`${baseUrl}/predictions`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-market-key": apiKey
    },
    body: JSON.stringify({ version: "bytedance/seedance-2.5", input })
  });

  if (response.status !== 201) {
    throw new Error(`API error: ${response.status} ${await response.text()}`);
  }

  const prediction = await response.json();
  return pollForResults(prediction.id);
}

const delay = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

async function pollForResults(predictionId) {
  const maxTimeout = 1200000;
  const pollInterval = 5000;
  const startTime = Date.now();

  while (Date.now() - startTime < maxTimeout) {
    const response = await fetch(`${baseUrl}/predictions/${predictionId}`, {
      headers: { "x-api-market-key": apiKey }
    });

    if (!response.ok) {
      throw new Error(`API error: ${response.status} ${await response.text()}`);
    }

    const prediction = await response.json();

    if (prediction.status === "succeeded") {
      return prediction.output;
    }

    if (prediction.status === "failed" || prediction.status === "canceled") {
      throw new Error(`Prediction ${prediction.status}: ${prediction.error || "Unknown error"}`);
    }

    await delay(pollInterval);
  }

  throw new Error("Prediction timed out after 20 minutes");
}

createAndWaitForPrediction({
  seed: 42,
  prompt: "a golden retriever puppy running across a green meadow toward the camera, slow motion, warm afternoon light",
  duration: 5,
  resolution: "480p"
}).then((output) => console.log(output));
```

#### Python
```python
import time
import requests

API_KEY = "YOUR_API_MARKET_KEY"
BASE_URL = "https://prod.api.market/api/v1/magicapi/multimodal-video-generator-bytedance-seedance-2-5"


def create_and_wait_for_prediction(input_data):
    headers = {"Content-Type": "application/json", "x-api-market-key": API_KEY}
    response = requests.post(
        f"{BASE_URL}/predictions",
        headers=headers,
        json={"version": "bytedance/seedance-2.5", "input": input_data},
    )

    if response.status_code != 201:
        raise Exception(f"API error: {response.status_code} {response.text}")

    return poll_for_results(response.json()["id"])


def poll_for_results(prediction_id):
    max_timeout = 1200
    poll_interval = 5
    headers = {"x-api-market-key": API_KEY}
    start_time = time.time()

    while time.time() - start_time < max_timeout:
        response = requests.get(f"{BASE_URL}/predictions/{prediction_id}", headers=headers)

        if response.status_code != 200:
            raise Exception(f"API error: {response.status_code} {response.text}")

        prediction = response.json()

        if prediction["status"] == "succeeded":
            return prediction["output"]

        if prediction["status"] in ("failed", "canceled"):
            raise Exception(f"Prediction {prediction['status']}: {prediction.get('error') or 'Unknown error'}")

        time.sleep(poll_interval)

    raise Exception("Prediction timed out after 20 minutes")


print(create_and_wait_for_prediction({
    "seed": 42,
    "prompt": "a golden retriever puppy running across a green meadow toward the camera, slow motion, warm afternoon light",
    "duration": 5,
    "resolution": "480p",
}))
```

## FAQ
- **How long can a video be?**
  - Up to 30 seconds. Set `duration` from 1 to 30, or -1 to let the model choose the length.
- **Can I start from an image?**
  - Yes. Send it as `image` to use it as the first frame, and optionally add `last_frame_image`. These cannot be combined with reference images, videos or audio; first/last-frame mode requires `aspect_ratio` `adaptive`.
- **How do I make a character speak?**
  - Keep `generate_audio` on and put the spoken line in double quotes in the prompt. For lip-sync to your own audio, send it in `reference_audios` together with at least one reference image or video.
- **Why is a request with a reference video more expensive?**
  - Requests with a non-empty `reference_videos` use a higher rate: $0.54431 per second at `480p` and $1.22356 per second at `720p`, against $0.13 and $0.29237 without one.
- **How much does the example cost?**
  - 5 seconds at `480p` without reference videos is 5 units: $0.65. The same request at the default `720p` costs $1.56.
- **What if my prediction fails?**
  - Failed predictions are not billed. Read the `error` field, adjust the input and try again.

## Contact Us
If you have any questions, reach out to us through the chat on the bottom right of the page. You can also email our support team at hello@magicapi.com.


Generate up to 30-second videos with native audio using ByteDance Seedance 2.5: text-to-video, first/last frame, and up to 30 reference images.