Kling Extend 3.0 — Extend Video

Extend an existing video using Kling Extend 3.0 via PixelByte API

POST /v1/jobs/submit

Kling Extend 3.0 — Extend Video

cURL

curl --request POST \
  --url https://api.muvi.video/v1/jobs/submit \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "<string>",
  "input": {
    "video_url": "<string>",
    "work_id": "<string>",
    "prompt": "<string>",
    "negative_prompt": "<string>",
    "quality": "<string>",
    "duration": "<string>"
  }
}
'

200

{
  "jobId": "<string>",
  "status": "<string>",
  "estimatedCompletionTime": "<string>",
  "costMicroCents": 123
}

Continue an existing video by generating new footage that follows on from the source clip with Kling Extend 3.0. Supports std/pro quality tiers and 5- or 10-second extensions.

Property	Value
Provider	Kling
Model	Kling Extend 3.0
Capability	Extend Video
Base Cost	70,000 micro-cents/second ($0.07/sec)
Processing Time	~240 seconds

Request Body

model · string · required

Model slug. Use kling/kling-extend-v3/extend-video.

input · object · required

Input parameters for video extension.

Hide properties

video_url · string · required

URL of the source video to extend.

work_id · string

Optional identifier of an existing Kling work to extend.

prompt · string

Text description guiding the extension (max 2500 characters).

negative_prompt · string

Text describing content to avoid (max 1000 characters).

quality · string

Generation quality. Default: std. Options: std, pro.

duration · string

Extension duration in seconds. Default: 5. Options: 5, 10.

webhookUrl · string

HTTPS URL to receive a webhook notification when the job completes or fails.

Pricing

Base cost: 70,000 micro-cents per second ($0.07/sec)

finalCost = baseCost × duration × quality

Factor	Option	Multiplier
Duration	5	5x
	10	10x
Quality	std	1x
	pro	1.5x

Default cost: 5 seconds, std quality = 70,000 × 5 × 1 = 350,000 micro-cents ($0.35)

Response

jobId · string

Unique identifier for the submitted job.

status · string

Initial job status. Always "pending" on successful submission.

estimatedCompletionTime · string

ISO 8601 timestamp of the estimated completion time.

costMicroCents · number

The cost of the job in micro-cents.

Code Examples

cURL

curl -X POST https://api.muvi.video/v1/jobs/submit \
  -H "Authorization: Bearer $PIXELBYTE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "kling/kling-extend-v3/extend-video",
    "input": {
      "video_url": "https://example.com/video.mp4",
      "prompt": "The character keeps walking forward into the open square",
      "quality": "std",
      "duration": "5"
    }
  }'