Kling 4.0 API

Strong motion and 1080p output.

Pricing
Resolution	Text or images	With video input
720p	Text or images31.4 Credits/s ($0.157/s)	With video input18 Credits/s ($0.09/s)
1080p	Text or images47 Credits/s ($0.235/s)	With video input27 Credits/s ($0.135/s)

With reference or editing video, billed seconds = max(input + output, 2 × output).

Full pricing ↓

Prompt

Resolution

Duration in seconds

Between 3 and 30 seconds.

Auto

The model picks the length, up to 30 s. You pay for the length it makes.

Aspect ratio

Text only: 16:9 when left empty; Auto is not available. With images: leave it empty to keep their shape, or pick Auto to match them.

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Pricing

Prices as of 2026-11-09

Tier	Price
720p	31.4 Credits/s ($0.157/s)^{Note 11}3–30 s
1080p	47 Credits/s ($0.235/s)^{Note 11}3–30 s
720p with video input 720p-video	18 Credits/s ($0.09/s)^{Notes 2, 32, 3}3–30 s
1080p with video input 1080p-video	27 Credits/s ($0.135/s)^{Notes 2, 32, 3}3–30 s

Holds Credits for up to 30 seconds and charges the actual length.
The rate applies to input and output seconds.
Holds Credits for up to 30 seconds of output plus up to 30 seconds of input, and charges the actual length.

1 Credit ≈ $0.005. At the standard pack price. Larger packs include bonus Credits, so each Credit costs less.

Delivery and billing

Output: Finished files are listed in the task result with an asset ID and type for each.
Download: Files are kept for 7 days and downloaded through short-lived signed links. You can delete them any time.
Billing: Credits are held when a task is accepted and charged on delivery. If generation fails, or nothing is delivered within 24 hours, the held Credits are released in full.
Notifications: Poll the task by ID, or use signed webhooks and deduplicate by event_id.

How is it billed?

By output second.

API reference

Create the task once, then poll it by its ID. Full script with upload and download · API reference

Request

API=https://api.vizoapi.com/v1
AUTH="Authorization: Bearer $VIZO_API_KEY"

# Create the task once and keep its ID.
ID=$(curl -fsS $API/generations -H "$AUTH" -H "Content-Type: application/json" \
  -d '{
  "model": "kling-4-0",
  "input": {
    "prompt": "A slow dolly shot through a rainy neon street",
    "settings": {
      "resolution": "720p",
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  },
  "metadata": {
    "client_reference": "my-unique-reference-1"
  }
}' | jq -r .id)

# Poll until the task closes, then read its status and result.
until curl -fsS $API/generations/$ID -H "$AUTH" | jq -e '.closed_at != null' > /dev/null; do sleep 5; done
curl -fsS $API/generations/$ID -H "$AUTH" | jq '{status, result}'

All fields

Send these fields in input. A field the table does not list is refused with HTTP 422 invalid_input.

Send either prompt for text-only generation or contents for images and videos, never both.
Exactly one prompt, up to 10 images and 5 videos (at most one base_video). Videos must be MP4/MOV, at most 300 MB each, 3–30 seconds each and at most 30 seconds total. Repeated feature_video, refer_image or middle_frame items require unique ids.
Repeated middle_frame, refer_image or feature_video entries require unique ids, cited in the prompt as @id.
aspect_ratio adaptive follows your input images, so it needs contents; a text-only request without aspect_ratio is 16:9.

Request parameters
Field	Description
`prompt`string	Required: exactly one of `prompt` or `contents` Text-only generation. Up to 26000 Latin or 11000 other characters, counted together. At most 26,000 characters
`contents`array of objects	Required: exactly one of `prompt` or `contents` Exactly one prompt, up to 10 images and 5 videos (at most one base_video). Videos must be MP4/MOV, at most 300 MB each, 3–30 seconds each and at most 30 seconds total. Repeated feature_video, refer_image or middle_frame items require unique ids. At least 1 items · At most 16 items
`contents[].type`stringRequired	Item kind. Allowed values`promptfirst_framemiddle_framelast_framerefer_imagefeature_videobase_video`
Items where `type` is `prompt`
`contents[].text`stringRequired	Prompt text. Up to 26000 Latin or 11000 other characters, counted together. At most 26,000 characters
Items where `type` is `first_frame`, `middle_frame`, `last_frame`, `refer_image`, `feature_video`, `base_video`
`contents[].url`stringRequired	An https URL or an uploaded asset id (ast_...). At most 4000 characters · Pattern`^(https://\|ast_)`
`contents[].id`stringOptional	Name cited in the prompt as @id. Unique within contents. At most 128 characters
`settings`objectOptional
`settings.resolution`stringOptional	Output resolution. Defaults to 1080p. Allowed values`720p1080p` Default `1080p`
`settings.duration`integerOptional	Output seconds, 3 to 30. Omit for automatic length: holds 30 seconds and settles delivered duration. Minimum 3 · Maximum 30
`settings.aspect_ratio`stringOptional	Output aspect ratio. A prompt request is 16:9 when this is left out and does not accept adaptive. With contents, leave it out to keep the shape of your frame images, or send adaptive to match your input images. Allowed values`21:916:99:161:1adaptive`

Full example request and response

A complete create request, the 202 answer and the task once it has succeeded. This input selects the 720p tier at 31.4 Credits per second. For 5 seconds the API holds 157.000 Credits.

Request

{
  "model": "kling-4-0",
  "input": {
    "prompt": "A paper boat drifting on a pond at dawn, slow dolly in",
    "settings": {
      "resolution": "720p",
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  },
  "metadata": {
    "client_reference": "my-unique-reference-1"
  }
}

202 Accepted

{
  "id": "gen_01JD8Z5QW3XR",
  "model": "kling-4-0",
  "source": "api",
  "created_at": "2026-11-08T09:00:00Z",
  "customer_resolution_deadline": "2026-11-09T09:00:00Z",
  "late_result_available": false,
  "metadata": {
    "client_reference": "my-unique-reference-1"
  },
  "status": "processing",
  "execution_status": "processing",
  "delivery_status": "pending",
  "billing_status": "pending",
  "version": 1,
  "price": {
    "unit": "credit",
    "estimated": "157.000",
    "reserved": "0.000",
    "charged": "0.000",
    "refunded": "0.000"
  },
  "allowed_actions": [],
  "closed_at": null,
  "error": null,
  "result": null
}

200 Succeeded

{
  "id": "gen_01JD8Z5QW3XR",
  "model": "kling-4-0",
  "source": "api",
  "created_at": "2026-11-08T09:00:00Z",
  "customer_resolution_deadline": "2026-11-09T09:00:00Z",
  "late_result_available": false,
  "metadata": {
    "client_reference": "my-unique-reference-1"
  },
  "status": "succeeded",
  "execution_status": "succeeded",
  "delivery_status": "ready",
  "billing_status": "settled",
  "version": 4,
  "price": {
    "unit": "credit",
    "estimated": "157.000",
    "reserved": "0.000",
    "charged": "157.000",
    "refunded": "0.000"
  },
  "allowed_actions": [],
  "closed_at": "2026-11-08T09:01:31Z",
  "error": null,
  "result": {
    "asset_id": "ast_01JD8Z9M2C4V",
    "outputs": [
      {
        "index": 0,
        "asset_id": "ast_01JD8Z9M2C4V",
        "content_type": "video/mp4"
      }
    ]
  }
}

Full API reference for Kling 4.0

Pricing

Delivery and billing

API reference

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