Generate fast, low-cost Kling 4.0 Flash videos from text. 3-20s clips at 720p with native audio. Pay per generation, no subscription. Kling 4.0 Flash Text-to-Video generates fast, low-cost 3-20 second 720p clips with native audio from a text prompt.
Kling 4.0 Flash Text-to-Video generates fast, low-cost 3-20 second 720p clips with native audio from a text prompt.
About this model
Kling 4.0 Flash Text-to-Video turns a text prompt into a 3-20 second 720p clip with native audio, in 16:9, 9:16, 1:1 or 21:9, at a lower per-second price than Kling 4.0. Describe the scene, camera and sound in the prompt and pick a duration up to 20 seconds. It is the quick, affordable choice for drafts, social clips and iteration. For 1080p and clips up to 30 seconds use Kling 4.0 Text to Video; to keep characters consistent use Kling 4.0 Flash Reference to Video, and to animate a still use Kling 4.0 Flash Keyframe to Video.
Cost analysis
| Provider | Cost | Notes |
|---|---|---|
| muapiapp | $0.094 per second ($0.47 per 5s clip) | $0.094/s of output video at 720p. |
$0.094/s of output video at 720p.
** Competitor pricing is estimated based on similar model architectures and usage tiers.
Configuration schema
| Parameter | Type | Description | Default |
|---|---|---|---|
| Prompt | string | Video description (max 8000 chars). | A lone astronaut walks across a red desert at sunrise, dust drifting past the camera, cinematic wide shot with wind and distant thunder |
| Duration | int | Video length in seconds (3-20). | 5 |
| Resolution | Enum (1 options) | Output resolution (Kling 4.0 Flash is 720p only). | 720p |
| Aspect Ratio | Enum (4 options) | Output aspect ratio. | 16:9 |
Video description (max 8000 chars).
A lone astronaut walks across a red desert at sunrise, dust drifting past the camera, cinematic wide shot with wind and distant thunderVideo length in seconds (3-20).
5Output resolution (Kling 4.0 Flash is 720p only).
720pOutput aspect ratio.
16:9Developer documentation
Write the prompt: Describe the subject, action, camera movement and sound (up to 8000 characters).
Configure output: duration (3-20s) and aspect_ratio (16:9, 9:16, 1:1, 21:9). Output is always 720p.
Submit and collect the result: The endpoint is async — poll /api/v1/predictions/{request_id}/result or pass a webhook_url.
curl -X POST https://api.muapi.ai/api/v1/kling-4.0-flash-text-to-video \
-H "Content-Type: application/json" \
-H "x-api-key: YOUR_API_KEY" \
-d '{"prompt": "A lone astronaut walks across a red desert at sunrise, dust drifting past the camera, cinematic wide shot", "duration": 10, "aspect_ratio": "16:9"}'
Frequently asked
3 to 20 seconds per clip at 720p. Flash does not offer 1080p; use Kling 4.0 for 1080p and up to 30 seconds.
16:9, 9:16, 1:1 and 21:9. The default is 16:9.
Yes, native audio is generated with the video.
$0.094 per second of output video, so a 5-second clip costs $0.47.
Flash is faster and cheaper but limited to 720p and 20 seconds. Kling 4.0 supports 1080p, up to 30 seconds and standalone voices.
The endpoint is asynchronous. Poll /api/v1/predictions/{request_id}/result or pass a webhook_url to be notified when the video is ready.