Extend an Existing Video
April 18, 2025 (October 1, 2025)
Table of contents
This endpoint extends a previously generated video, continuing the animation from where it left off.
https://api.useapi.net/v1/kling/videos/extend
Request Headers
Authorization: Bearer {API token}
Content-Type: application/json
# Alternatively you can use multipart/form-data
# Content-Type: multipart/form-data
API tokenis required, see Setup useapi.net for details.
Request Body
{
"email": "[email protected]",
"task_id": "12345678",
"prompt": "Continue with the mountain landscape, now showing a sunset",
"negative_prompt": "people, low quality, distorted",
"cfg_scale": 0.5,
"replyUrl": "https://your-callback-url.com/webhook",
"replyRef": "your-reference-id"
}
-
emailis optional when only one account configured.
However, if you have multiple accounts configured, this parameter becomes required. -
task_idis required, the ID of a completed video generation task to extend.
You can get a list of your tasks from GET /tasks. -
promptis optional, text description to guide the extended video generation.
Maximum length: 2500 characters. -
negative_promptis optional, what not to include in the generated video.
Maximum length: 2500 characters. -
cfg_scaleis optional, guidance scale for video extension.
Range:0to1. Default:0.5. -
enable_audiois optional, add sound effects.
Supported values:false(default) ortrue. -
maxJobsis optional, range from1to50.
Specifies the maximum number of concurrent jobs. -
replyUrlis optional, a callback URL to receive generation progress and result.
See GET /tasks/task_idfor response model. -
replyRefis optional, a reference identifier for the callback.
Note: The task specified by task_id must be in the succeed status for the extension to work.
Responses
-
{ "task": { "id": 123456789, "userId": 12345, "type": "m2v_extend_video", "scene": "NORMAL_CREATION", "status": 5, "status_name": "submitted", "status_final": false, "taskInfo": { "type": "m2v_extend_video", "inputs": [ { "name": "input", "inputType": "URL", "token": null, "blobStorage": null, "url": "https://s21-kling.klingai.com/video12345.mp4", "cover": null, "fromWorkId": 12345678 } ], "arguments": [ { "name": "prompt", "value": "Continue with the mountain landscape, now showing a sunset" }, { "name": "negative_prompt", "value": "people, low quality, distorted" }, { "name": "cfg", "value": "0.5" }, { "name": "__initialType", "value": "m2v_txt2video_hq" }, { "name": "__initialPrompt", "value": "A majestic mountain landscape with snow-capped peaks and flowing rivers" }, { "name": "kling_version", "value": "1.6" } ], "extraArgs": {}, "callbackPayloads": [], "scene": "NORMAL_CREATION" }, "favored": false, "deleted": false, "viewed": false, "createTime": 1745376611075, "updateTime": 1745376611075 }, "works": [], "status": 5, "status_name": "submitted", "status_final": false, "message": "", "limitation": { "type": "m2v_extend_video", "remaining": 10000, "limit": 10000 }, "userPoints": { "points": [], "total": 0 }, "userTickets": { "ticket": [] }, "editProject": null } -
{ "error": "Task is not completed" } -
{ "error": "Unauthorized", "code": 401 } -
Kling uses a
500response to indicate moderation and other issues with the input. It may be hard to separate actual 500 errors from moderation errors, so use theerrorfield text and your best judgement to tell them apart, since themessagefield most often has very generic and perhaps misleading text.{ "error": "The content you uploaded appears to violate the community guidelines. (CM_EXT.POther)", "message": "Service busy (CM_EXT.POther)" }
When successful, the response includes a task ID which can be used to check the status using GET /tasks/task_id.
Model
{ // TypeScript, all fields are optional
task: {
id: number
userId: number
type: string
scene: string
status: number
status_name: 'submitted' | 'failed' | 'processing' | 'succeed'
status_final: boolean
taskInfo: {
type: string
inputs: Array<{
name: string
inputType: string
token: string | null
blobStorage: any | null
url: string
cover: string | null
fromWorkId: number | null
}>
arguments: Array<{
name: string
value: string
}>
extraArgs: Record<string, any>
callbackPayloads: any[]
scene: string
}
favored: boolean
deleted: boolean
viewed: boolean
createTime: number
updateTime: number
viewTime: number
}
works: Array<any>
status: number
status_name: 'submitted' | 'failed' | 'processing' | 'succeed'
status_final: boolean
message: string
error: string
limitation: {
type: string
remaining: number
limit: number
}
userPoints: {
points: Array<{
orderId: string
type: string
amount: number
balance: number
startTime: number
endTime: number
}>
total: number
}
userTickets: {
ticket: Array<{
orderId: string
type: string
packageType: string
amount: number
balance: number
startTime: number
endTime: number
}>
}
editProject: any | null
}
Examples
-
curl -X POST "https://api.useapi.net/v1/kling/videos/extend" \ -H "Content-Type: application/json" \ -H "Authorization: Bearer …" \ -d '{ "email": "[email protected]", "task_id": "12345678", "prompt": "Continue with the mountain landscape, now showing a sunset", "negative_prompt": "people, low quality, distorted" }' -
const token = "API token"; const email = "Previously configured account email"; const apiUrl = "https://api.useapi.net/v1/kling/videos/extend"; const response = await fetch(apiUrl, { method: "POST", headers: { "Content-Type": "application/json", "Authorization": `Bearer ${token}`, }, body: JSON.stringify({ email: email, task_id: "12345678", prompt: "Continue with the mountain landscape, now showing a sunset", negative_prompt: "people, low quality, distorted" }) }); const result = await response.json(); console.log("response", {response, result}); -
import requests token = "API token" email = "Previously configured account email" apiUrl = "https://api.useapi.net/v1/kling/videos/extend" headers = { "Content-Type": "application/json", "Authorization" : f"Bearer {token}" } data = { "email": email, "task_id": "12345678", "prompt": "Continue with the mountain landscape, now showing a sunset", "negative_prompt": "people, low quality, distorted" } response = requests.post(apiUrl, headers=headers, json=data) print(response, response.json())