# Kling 4.0 API

> Kuaishou's newest Kling: up to 30 seconds at 720p or 1080p, always with stereo sound, from text, a first and last frame, or up to 10 reference images. By Kuaishou, on Revana from $0.11 per second of video.

- Model id: `kling-4.0`
- Kind: video
- Maker: Kuaishou
- Tasks: Text to video, Image to video, First + last frame, Reference to video, Video to video
- Resolutions: 720p, 1080p
- Durations: 3 to 30 seconds
- Aspect ratios: 16:9, 9:16, 1:1, 21:9
- Audio: supported (`"audio": true`)
- Input images: up to 10
- Routes: 2 (starts on the cheapest, falls back automatically)
- Status: live on the API
- Page: https://revana.si/models/kling-4.0

## Price (per second of video, USD)

| Resolution | Price | Credits |
|---|---|---|
| 720p | $0.18 | 18 |
| 720p + with video input | $0.11 | 11 |
| 1080p | $0.27 | 27 |
| 1080p + with video input | $0.16 | 16 |

100 credits = $1. Charged once, only for the route that succeeds; failed generations cost nothing.

## Request

POST https://api.revana.si/v1/generations with `Authorization: Bearer $REVANA_API_KEY`:

```json
{
  "model": "kling-4.0",
  "input": {
    "prompt": "A slow dolly shot through a neon-lit night market in the rain, steam rising from food stalls",
    "resolution": "720p",
    "duration": 3,
    "aspect_ratio": "16:9",
    "audio": true
  }
}
```

Poll `GET /v1/generations/{id}` until `status` is `succeeded` or `failed`, then download `GET /v1/generations/{id}/content`. Full API: https://revana.si/llms.txt

## Similar models

- [Kling 2.6 Pro](https://revana.si/models/kling-2.6-pro.md): from $0.07 per second of video
- [Kling 3.0](https://revana.si/models/kling-3.0.md): from $0.09 per second of video
- [Kling 2.1 Master](https://revana.si/models/kling-2.1-master.md): from $0.20 per second of video
- [Kling 2.1 Pro](https://revana.si/models/kling-2.1-pro.md): from $0.07 per second of video
- [Kling 2.1 Standard](https://revana.si/models/kling-2.1-std.md): from $0.04 per second of video
- [Kling 2.5 Turbo Pro](https://revana.si/models/kling-2.5-turbo-pro.md): from $0.06 per second of video