Use Videos Video Extend with Comfy Router

API Reference for kling/videos-video-extend, served by Comfy Router from Kling.

Quick start

Create a key in your Comfy workspace and export it as COMFY_API_KEY. The Python and TypeScript snippets use the Comfy SDKs (pip install comfy-sdk, npm install @comfyorg/sdk); the cURL snippet is the same call over raw HTTP. Model ID: kling/videos-video-extend Endpoint: POST https://api.comfy.org/v2/models/kling/videos-video-extend

from comfy_sdk import Comfy

# Reads COMFY_API_KEY from the environment.
# The SDK automatically creates an idempotency key and reuses it for automatic retries.
with Comfy() as client:
    result = client.models.run(
        "kling/videos-video-extend",
        {
            "cfg_scale": 0.5,
            "prompt": "The camera keeps drifting forward down the alley.",
            "video_id": "kling-video-6f5e4d3c2b1a",
        },
    )

print(result)

import { comfy } from "@comfyorg/sdk";

// Reads COMFY_API_KEY from the environment.
// The SDK automatically creates an idempotency key and reuses it for automatic retries.
const { data } = await comfy.models.run("kling/videos-video-extend", {
  cfg_scale: 0.5,
  prompt: "The camera keeps drifting forward down the alley.",
  video_id: "kling-video-6f5e4d3c2b1a",
});

console.log(data);

curl https://api.comfy.org/v2/models/kling/videos-video-extend \
  -H "X-API-Key: $COMFY_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d "{\"cfg_scale\": 0.5, \"prompt\": \"The camera keeps drifting forward down the alley.\", \"video_id\": \"kling-video-6f5e4d3c2b1a\"}"

Schema

Input

string (uri)

The callback notification address. Server will notify when the task status changes.Format: uri

number

default:"0.5"

Flexibility in video generation. The higher the value, the lower the model’s degree of flexibility, and the stronger the relevance to the user’s prompt.Range: 0 to 1Format: float

string

Negative text prompt for elements to avoid in the extended video

string

Positive text prompt for guiding the video extension

string

required

The ID of the video to be extended. Supports videos generated by text-to-video, image-to-video, and previous video extension operations. Cannot exceed 3 minutes total duration after extension.

Generated from the schema Router serves at GET /v2/models/kling/videos-video-extend/openapi.json, the same document it validates a call against before the request reaches the provider.

Output

integer

Error code

object

integer

Task creation time, Unix timestamp in milliseconds

string

The deduction units of task

string

Task ID

object

string

object

object[]

string

Total video duration in seconds

string

Generated video ID

string (uri)

URL for generated videoFormat: uri

string (uri)

URL for generated video with watermark, hotlink protection formatFormat: uri

string

Task StatusPossible values: submitted, processing, succeed, failed

string

Task status information, displaying the failure reason when the task fails

integer

Task update time, Unix timestamp in milliseconds

object

boolean

string

Error message

string

Request ID

Examples

Input

{
  "cfg_scale": 0.5,
  "prompt": "The camera keeps drifting forward down the alley.",
  "video_id": "kling-video-6f5e4d3c2b1a"
}

Output

{
  "code": 0,
  "data": {
    "created_at": 1798761600000,
    "task_id": "kling-video-extend-task-0a1b2c3d4e5f",
    "task_result": {
      "videos": [
        {
          "duration": "10",
          "id": "kling-video-5f4e3d2c1b0a",
          "url": "https://example.invalid/kling/videos-video-extend/generated.mp4"
        }
      ]
    },
    "task_status": "succeed",
    "updated_at": 1798762020000
  },
  "message": "SUCCEED",
  "request_id": "c7b6a504-3f2e-41d0-8a9c-6b5d4e3f2a10"
}

Before you ship

The SDKs create an Idempotency-Key and reuse it for automatic retries. For manual retries, reuse the original key. Router can hold the connection for up to 10 minutes. When a request fails, Router sends an X-Comfy-Error-Type response header explaining why. A 422 means Router rejected the input before calling the provider. Download generated assets promptly because result URLs can expire.

Headers

Authentication, idempotency, request IDs, error buckets, retry pacing, spend limits.

Using the Router API

Model discovery, validation errors, retries, and billing.

Limitations

What Router does not do today, and what to use instead.

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Specifications

Use Videos Video Extend with Comfy Router

Quick start

Schema

Input

Output

Examples

Input

Output

Before you ship

Headers

Using the Router API

Limitations

​Quick start

​Schema

​Input

​Output

​Examples

​Input

​Output

​Before you ship

Headers

Using the Router API

Limitations

Quick start

Schema

Input

Output

Examples

Input

Output

Before you ship