Kling 4.0

Kling 4.0 API. The newest Kling video model: text-to-video and image-to-video, 3-30 seconds, 720p or 1080p, 21:9 to 9:16.

POST/v1/media/queue

from $0.267/second

Overview

Kling 4.0 — the newest Kling video model, with clips up to 30 seconds at 720p or 1080p and ultrawide 21:9 framing. Async operation — submit a job, poll for completion.

Property	Value
Model ID	`kwaivgi/kling-v4.0`
Alias	`kling-4`, `kling-4.0`
Provider	Kling
Inputs	text-to-video, image-to-video
Resolutions	720p, 1080p
Aspect Ratios	21:9, 16:9, 9:16, 1:1
Duration	3–30 seconds
Audio Generation	Not supported
Billing	Per job — priced when queued, charged only on success
Pricing	from $0.267/second

Usage

All media models use the async job queue. Submit a job, then poll for the result.

Step 1: Submit Job

Text-to-Video

const res = await fetch('https://api.yepapi.com/v1/media/queue', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    model: 'kwaivgi/kling-v4.0',
    prompt: 'A cinematic drone shot over a rugged coastline at golden hour',
    options: {
      aspectRatio: '16:9',
      resolution: '1080p',
      duration: '5',
    },
  }),
});
const { data } = await res.json();
// data.jobId — use this to poll for results

curl -X POST https://api.yepapi.com/v1/media/queue \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "kwaivgi/kling-v4.0", "prompt": "A cinematic drone shot over a rugged coastline", "options": {"aspectRatio": "16:9", "resolution": "1080p", "duration": "5"}}'

Image-to-Video

Pass a starting image via imageData to animate it.

const res = await fetch('https://api.yepapi.com/v1/media/queue', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    model: 'kwaivgi/kling-v4.0',
    prompt: 'Animate this scene — clouds drifting, light changing',
    options: {
      resolution: '1080p',
      duration: '5',
    },
    imageData: {
      mimeType: 'image/jpeg',
      base64: '...', // Base64-encoded image
    },
  }),
});

curl -X POST https://api.yepapi.com/v1/media/queue \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "kwaivgi/kling-v4.0", "prompt": "Animate this scene — clouds drifting, light changing", "options": {"resolution": "1080p", "duration": "5"}, "imageData": {"mimeType": "image/jpeg", "base64": "..."}}'

Step 2: Poll for Result

const status = await fetch(`https://api.yepapi.com/v1/media/status/${data.jobId}`, {
  headers: { 'x-api-key': 'YOUR_API_KEY' },
});
const { data: job } = await status.json();
// job.status — "pending" | "processing" | "completed" | "failed"
// job.result.video — { mimeType, base64 } when completed

curl https://api.yepapi.com/v1/media/status/JOB_ID \
  -H "x-api-key: YOUR_API_KEY"

Request Body

Parameter	Type	Required	Description	Default
`model`	`string`	Yes	`kwaivgi/kling-v4.0` or aliases `kling-4`, `kling-4.0`	—
`prompt`	`string`	Yes	Text description of the video to generate	—
`options.aspectRatio`	`string`	No	One of: 21:9, 16:9, 9:16, 1:1 (text-to-video only)	`16:9`
`options.resolution`	`string`	No	`720p`, `1080p`	`1080p`
`options.duration`	`string` or `number`	No	`3` to `30` (seconds)	`5`
`imageData.mimeType`	`string`	No	MIME type of input image (image/png, image/jpeg, image/webp)	—
`imageData.base64`	`string`	No	Base64-encoded input image for image-to-video generation	—

Options are validated when you submit: an unsupported duration, resolution or value returns 400 naming the allowed values.

Features

Text-to-video and image-to-video
3–30 seconds, the longest Kling clips
720p or 1080p
21:9, 16:9, 9:16 and 1:1 (text-to-video)

Pricing

Tier	≈ Cost/sec	5-second video
720p	$0.267	$1.34
1080p	$0.40	$2.00

Prices shown are for a 5-second clip at the default settings; longer clips cost proportionally more. Each job is priced when it's queued — the exact quote for your duration, resolution and options — and charged only if it succeeds. Failed or moderated jobs are free.

Info

Video jobs can take several minutes to complete. When capacity is busy, jobs wait in the queue (status stays pending or processing) — no action needed. Results retained for 1 hour.

Under the Hood

Kling 4.0

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