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# Kling 4.0 Flash

> The faster, lower-cost Kling 4.0: 3 to 20 second clips at 720p with native audio from text, a first frame, reference images and videos, or a video to edit.

![Kling 4.0 Flash](https://media.empiriolabs.ai/model-logos/kling-4-0-flash.png)

[Kling AI](/providers/kling) · Video Generation

`POST /v1/videos/generations`

The faster, lower-cost Kling 4.0: 3 to 20 second clips at 720p with native audio from text, a first frame, reference images and videos, or a video to edit.

## At a glance

| Field               | Value                                                           |
| ------------------- | --------------------------------------------------------------- |
| Model id            | `kling-4-0-flash`                                               |
| Model release date  | 2026-11-04                                                      |
| Input modalities    | Text, Image, Video                                              |
| Output modalities   | Video                                                           |
| Context window      | -                                                               |
| Weight precision    | -                                                               |
| Features            | video_generation, text_to_video, image_to_video, audio, editing |
| Native inference    | No                                                              |
| New                 | Yes                                                             |
| Supported endpoints | `POST /v1/videos/generations`                                   |
| Alternate model ids | `kling-4.0-flash`, `kling/kling-4-0-flash`                      |

## Pricing

| Charge           | Spec                                                       | Rate    |
| ---------------- | ---------------------------------------------------------- | ------- |
| Standard 720p    | per second                                                 | \$0.094 |
| Video input 720p | per second of input plus output, at least twice the output | \$0.063 |

## Example request

```bash
curl https://api.empiriolabs.ai/v1/videos/generations \
  -H 'Authorization: Bearer $EMPIRIOLABS_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"model": "kling-4-0-flash", "prompt": "sunrise over the ocean", "duration": 6}'
```

## Parameters

| Parameter          | Type   | Required | Default  | Description                                                                                                                                                                                         |
| ------------------ | ------ | -------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `prompt`           | string | yes      | -        | Scene description, up to 26,000 English or 11,000 non-English characters. Refer to reference images as @image_1, @image_2 and videos as @video_1 in the order they are supplied.                    |
| `resolution`       | enum   | no       | `"720p"` | Output resolution. · Allowed: `720p`                                                                                                                                                                |
| `aspect_ratio`     | enum   | no       | `"16:9"` | Output aspect ratio for text-to-video and references. A first frame on its own, or a video to edit, sets the aspect ratio instead. · Allowed: `16:9`, `9:16`, `1:1`, `21:9`                         |
| `duration`         | number | no       | `5`      | Clip length in seconds, whole numbers only. A video edit keeps the length of the video it edits. · Range: 3 – 20                                                                                    |
| `image`            | string | no       | -        | First frame image URL. The video starts on this image.                                                                                                                                              |
| `reference_images` | string | no       | -        | Reference image URLs for characters, objects, scenes or style, as a list or comma-separated. Up to 10 images in total.                                                                              |
| `video`            | string | no       | -        | Video URL to edit, 3 to 20 seconds. The result keeps its length, and bills at the video input rate.                                                                                                 |
| `reference_videos` | string | no       | -        | Reference video URLs for motion, camera work or style, 3 to 20 seconds each and 20 seconds of video in total, as a list or comma-separated. Up to 5 videos in total. Bills at the video input rate. |

## Notes

Generates 3 to 20 second clips at 24 fps in 720p, each with a native stereo audio track.

**Inputs**

* Text to video: prompt only.
* First frame (`image`): the video starts on this image and follows its aspect ratio.
* Reference images (`reference_images`): characters, objects, scenes or style to use. A first frame can be sent with them.
* Reference videos (`reference_videos`): motion, camera work or style to follow, 3 to 20 seconds each.
* Video edit (`video`): a video to edit, 3 to 20 seconds. The result keeps its length.
* Up to 10 images and 5 videos per request, with at most 20 seconds of video in total. In the prompt, refer to reference images as @image_1, @image_2 and to videos as @video_1, @video_2 (the video to edit first).
* Last and middle frames and 1080p are available on Kling 4.0.

**In the Playground**

One attached image is the first frame, and two or more are references. The first attached video is the one edited; any others are references.

**Media limits**

* Images: JPG or PNG, at least 300 px, aspect ratio between 2:5 and 5:2, up to 30 MB.
* Videos: MP4 or MOV, 3 to 20 seconds, 700 to 4553 px per side, 24 to 60 fps, up to 300 MB.

**Billing**

* Without a video input: billed per second of the generated clip.
* With a video input (a video to edit or a reference video): billed at the video input rate on twice the length of the generated clip, or on the input plus the output when the input is longer.

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*Machine-readable schema:* `GET https://api.empiriolabs.ai/v1/models/kling-4-0-flash`.