> ## Documentation Index
> Fetch the complete documentation index at: https://docs.flatkey.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Seedance Video Generation — POST /v1/videos

> Create Seedance video tasks with text and multimodal inputs, poll their status, and download completed videos through Flatkey.

Use `POST /v1/videos` to create an asynchronous Seedance video-generation task. Poll the task until it completes, then download the video from the returned Flatkey URL.

Supported models include `seedance-2.0` and `seedance-2.0-fast`. Availability depends on your account; use [`GET /v1/models`](/api-reference/models) to retrieve the current model list.

## Endpoint

```http theme={"dark"}
POST https://router.flatkey.ai/v1/videos
```

<Note>
  Flatkey also accepts `POST /v1/video/generations` and `GET /v1/video/generations/{task_id}`. Use `/v1/videos` for the standard response structure and native `usage` data.
</Note>

## Request

### Headers

| Header          | Value                     |
| --------------- | ------------------------- |
| `Authorization` | `Bearer $FLATKEY_API_KEY` |
| `Content-Type`  | `application/json`        |

### Body parameters

<ParamField body="model" type="string" required>
  Seedance model ID. Use `"seedance-2.0"` or `"seedance-2.0-fast"`.
</ParamField>

<ParamField body="content" type="array" required>
  Multimodal input items. Include at least one non-empty text item, image URL, or video URL.
</ParamField>

<ParamField body="resolution" type="string">
  Output resolution: `"480p"`, `"720p"`, or `"1080p"`.
</ParamField>

<ParamField body="ratio" type="string">
  Output aspect ratio: `"16:9"`, `"4:3"`, `"1:1"`, `"3:4"`, `"9:16"`, `"21:9"`, or `"adaptive"`.
</ParamField>

<ParamField body="duration" type="integer">
  Video duration from 4 through 15 seconds. Use `-1` to let the model choose.
</ParamField>

<ParamField body="seed" type="integer">
  Random seed. Omit it to use a random seed.
</ParamField>

<ParamField body="watermark" type="boolean">
  Whether to add a watermark. Default: `false`.
</ParamField>

<ParamField body="generate_audio" type="boolean">
  Whether to generate synchronized audio.
</ParamField>

### `content` items

| `type`      | Value field     | Supported `role`                               | Purpose                                               |
| ----------- | --------------- | ---------------------------------------------- | ----------------------------------------------------- |
| `text`      | `text`          | —                                              | Text prompt. Multiple text items are joined in order. |
| `image_url` | `image_url.url` | `first_frame`, `last_frame`, `reference_image` | Input or reference image. Up to 9 images.             |
| `video_url` | `video_url.url` | `reference_video`                              | Reference video. Up to 3 videos.                      |
| `audio_url` | `audio_url.url` | `reference_audio`                              | Reference audio. Up to 3 clips.                       |

If an image uses the `first_frame` or `last_frame` role, the API uses first/last-frame mode. Other images are treated as references.

### Advanced parameters

<ParamField body="input_type" type="string">
  Explicit input mode: `"reference"` or `"first_last_frame"`. Omit it to infer the mode from `content`.
</ParamField>

<ParamField body="web_search" type="boolean">
  Enable web-search augmentation for the task.
</ParamField>

<ParamField body="super_resolution_config" type="object">
  Upscale the generated video while retaining the same public task ID.

  <Expandable title="super_resolution_config fields">
    <ParamField body="resolution" type="string">
      Target resolution: `"720p"`, `"1080p"`, `"2k"`, or `"4k"`. It must exceed the original resolution and cannot be combined with `resolution_limit`.
    </ParamField>

    <ParamField body="resolution_limit" type="integer">
      Custom short-edge pixel limit from 64 through 2160. It cannot be combined with `resolution`.
    </ParamField>

    <ParamField body="scene" type="string">
      Upscaling scene: `"aigc"`, `"short_series"`, `"ugc"`, or `"old_film"`.
    </ParamField>

    <ParamField body="tool_version" type="string">
      Upscaling mode: `"standard"` (default) or `"professional"`.
    </ParamField>

    <ParamField body="fps" type="integer">
      Output frame rate from 1 through 120. Values above the source frame rate enable frame interpolation.
    </ParamField>
  </Expandable>
</ParamField>

<Warning>
  `camera_fixed`, `frames`, `callback_url`, and `return_last_frame` are accepted for compatibility but currently have no effect.
</Warning>

## Example requests

<CodeGroup>
  ```python python theme={"dark"}
  import os
  import requests

  response = requests.post(
      "https://router.flatkey.ai/v1/videos",
      headers={
          "Authorization": f"Bearer {os.environ['FLATKEY_API_KEY']}",
          "Content-Type": "application/json",
      },
      json={
          "model": "seedance-2.0",
          "content": [
              {
                  "type": "text",
                  "text": "An astronaut walking on the moon, cinematic lighting, slow camera push-in",
              }
          ],
          "resolution": "1080p",
          "ratio": "16:9",
          "duration": 5,
      },
  )
  response.raise_for_status()
  print(response.json())
  ```

  ```javascript node theme={"dark"}
  const response = await fetch("https://router.flatkey.ai/v1/videos", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.FLATKEY_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      model: "seedance-2.0",
      content: [
        {
          type: "text",
          text: "An astronaut walking on the moon, cinematic lighting, slow camera push-in",
        },
      ],
      resolution: "1080p",
      ratio: "16:9",
      duration: 5,
    }),
  });

  if (!response.ok) throw new Error(await response.text());
  console.log(await response.json());
  ```

  ```bash curl theme={"dark"}
  curl https://router.flatkey.ai/v1/videos \
    -H "Authorization: Bearer $FLATKEY_API_KEY" \
    -H "Content-Type: application/json" \
    -d '{
      "model": "seedance-2.0",
      "content": [
        {
          "type": "text",
          "text": "An astronaut walking on the moon, cinematic lighting, slow camera push-in"
        }
      ],
      "resolution": "1080p",
      "ratio": "16:9",
      "duration": 5
    }'
  ```
</CodeGroup>

### First- and last-frame input

```json theme={"dark"}
{
  "model": "seedance-2.0",
  "content": [
    { "type": "text", "text": "The camera slowly moves forward" },
    {
      "type": "image_url",
      "image_url": { "url": "https://example.com/first.jpg" },
      "role": "first_frame"
    },
    {
      "type": "image_url",
      "image_url": { "url": "https://example.com/last.jpg" },
      "role": "last_frame"
    }
  ],
  "resolution": "720p",
  "ratio": "16:9",
  "duration": 5
}
```

### Multimodal reference with upscaling

```json theme={"dark"}
{
  "model": "seedance-2.0",
  "content": [
    { "type": "text", "text": "A woman smiles at the camera during a beach sunset" },
    {
      "type": "image_url",
      "image_url": { "url": "https://example.com/reference.jpg" },
      "role": "reference_image"
    }
  ],
  "resolution": "1080p",
  "ratio": "16:9",
  "duration": 5,
  "watermark": false,
  "super_resolution_config": {
    "resolution": "4k",
    "scene": "aigc",
    "tool_version": "professional",
    "fps": 60
  }
}
```

## Response

```json theme={"dark"}
{
  "id": "task_3f9a00000000000000000000000000e2",
  "task_id": "task_3f9a00000000000000000000000000e2",
  "object": "video",
  "model": "seedance-2.0",
  "status": "queued",
  "progress": 0,
  "created_at": 1780306574
}
```

### Response fields

<ResponseField name="id" type="string">
  Public task ID used to poll the task and download the completed video. `task_id` contains the same value.
</ResponseField>

<ResponseField name="status" type="string">
  Task status: `queued`, `in_progress`, `completed`, or `failed`.
</ResponseField>

<ResponseField name="progress" type="integer">
  Generation progress from 0 through 100.
</ResponseField>

<ResponseField name="created_at" type="integer">
  Unix timestamp for task creation.
</ResponseField>

## Poll task status

```http theme={"dark"}
GET https://router.flatkey.ai/v1/videos/{task_id}
```

```bash theme={"dark"}
curl https://router.flatkey.ai/v1/videos/task_3f9a00000000000000000000000000e2 \
  -H "Authorization: Bearer $FLATKEY_API_KEY"
```

While generation is running, the response includes the current progress:

```json theme={"dark"}
{
  "id": "task_3f9a00000000000000000000000000e2",
  "object": "video",
  "status": "in_progress",
  "progress": 50,
  "model": "seedance-2.0",
  "created_at": 1780306574
}
```

When the task completes, the response includes the video URL and token usage:

```json theme={"dark"}
{
  "id": "task_3f9a00000000000000000000000000e2",
  "object": "video",
  "status": "completed",
  "progress": 100,
  "model": "seedance-2.0",
  "usage": {
    "completion_tokens": 120,
    "total_tokens": 120
  },
  "metadata": {
    "url": "https://router.flatkey.ai/v1/videos/task_3f9a00000000000000000000000000e2/content"
  },
  "created_at": 1780306574,
  "completed_at": 1780306750
}
```

Failed tasks return the error details with the task response:

```json theme={"dark"}
{
  "id": "task_3f9a00000000000000000000000000e2",
  "object": "video",
  "status": "failed",
  "error": {
    "message": "The video generation task failed.",
    "code": "video_generation_failed"
  }
}
```

Any pre-consumed balance is refunded automatically.

### Status values

| Status        | Meaning                                                                                                |
| ------------- | ------------------------------------------------------------------------------------------------------ |
| `queued`      | The task is waiting to start.                                                                          |
| `in_progress` | The video is being generated. `progress` ranges from 0 through 100.                                    |
| `completed`   | The video is ready at `metadata.url`, and token usage is available in `usage`.                         |
| `failed`      | Generation failed. Details are available in `error.message`, and any pre-consumed balance is refunded. |

## Download the video

```http theme={"dark"}
GET https://router.flatkey.ai/v1/videos/{task_id}/content
```

```bash theme={"dark"}
curl -L "https://router.flatkey.ai/v1/videos/task_3f9a00000000000000000000000000e2/content" \
  -o output.mp4
```

The content endpoint streams `video/mp4` data. It does not require a Bearer token and can be used directly as a `<video>` source.

<Warning>
  The content endpoint works only after the task completes and is rate-limited by client IP. Treat the URL as sensitive because anyone with it can download the video.
</Warning>

## Errors

Request-time errors use Flatkey's standard error envelope:

```json theme={"dark"}
{
  "error": {
    "message": "...",
    "type": "...",
    "code": "..."
  }
}
```

| Scenario                  | Behavior                                                               |
| ------------------------- | ---------------------------------------------------------------------- |
| Empty `content`           | The request is rejected. Include non-empty text, an image, or a video. |
| Unavailable model         | The requested `model` is not enabled for the route.                    |
| Insufficient balance      | The task is not created.                                               |
| Temporary service failure | Retry later using your normal backoff policy.                          |

## End-to-end example

This example creates a task, polls it every five seconds, and downloads the completed video. It requires [`jq`](https://jqlang.github.io/jq/).

```bash theme={"dark"}
#!/usr/bin/env bash
set -euo pipefail

BASE="https://router.flatkey.ai"
: "${FLATKEY_API_KEY:?Set FLATKEY_API_KEY before running this script}"

RESPONSE=$(curl -sS "$BASE/v1/videos" \
  -H "Authorization: Bearer $FLATKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "seedance-2.0",
    "content": [
      { "type": "text", "text": "An astronaut walking on the moon, cinematic lighting" }
    ],
    "resolution": "1080p",
    "ratio": "16:9",
    "duration": 5
  }')

TASK_ID=$(echo "$RESPONSE" | jq -r '.id')
echo "task: $TASK_ID"

while true; do
  RESULT=$(curl -sS "$BASE/v1/videos/$TASK_ID" \
    -H "Authorization: Bearer $FLATKEY_API_KEY")
  STATUS=$(echo "$RESULT" | jq -r '.status')
  echo "status: $STATUS"

  [ "$STATUS" = "completed" ] && break
  if [ "$STATUS" = "failed" ]; then
    echo "failed: $(echo "$RESULT" | jq -r '.error.message')" >&2
    exit 1
  fi
  sleep 5
done

VIDEO_URL=$(echo "$RESULT" | jq -r '.metadata.url')
curl -L "$VIDEO_URL" -o output.mp4
echo "saved -> output.mp4"
```