Kling 4.0 API
Kling 4.0 video generation, editing, extension and billing
Generate, edit and extend 3–30 second videos at 720p/1080p with stereo audio.
Provider
Kling AIModel ID
kling-v4Endpoint
POST /api-platform/v1/generationsAuthentication
Base URL: https://aihub-admin.aimix.pro. Send Authorization: Bearer <PIXMIND_API_KEY> on both creation and polling requests, and Content-Type: application/json when submitting JSON. Keep your key in a server environment variable.
Model notes
- Five modes: text-to-video, image-to-video, reference, edit and extend. Poll the returned PixMind task ID using GET /api-platform/v1/tasks/{taskId}.
- Editing or reference videos: bill output seconds + max(output seconds, input seconds). Probe input duration, round up its sum and cap at 30 seconds. Editing without duration follows input; extension bills only the new segment. Failed tasks are fully refunded.
- Exactly one first frame, at most one last frame and eight keyframes (10 total). References: 10 images, 5 videos (30 seconds total), 3 audio clips (5–30 seconds each), 15 assets combined. Use public HTTP(S) URLs.
- No mode=std/pro/4k, negative_prompt, watermark=true or audio=false. Extension does not accept aspect_ratio or audio_setting. API is charged at the supplied official USD list rates; wallet points are rounded up once per request.
Request parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
model | string | Yes | Stable PixMind model ID. Use `kling-v4`. Allowed values: |
prompt | string | No | Required except for image-to-video. |
resolution | string | No | Output video resolution. Allowed values: Default: |
duration | integer | No | Requested clip duration in seconds. Allowed values: Default: |
aspectRatio | string | No | Requested output aspect ratio. Allowed values: Default: |
imageUrl | string (URI) | No | Starting image for image-to-video generation. |
first_frame_image | string | No | First frame URL; do not mix with other image input forms. |
last_frame_image | string | No | Last frame or extension target frame URL. |
omni_reference_task_type | string | No | auto (default), reference, edit or extend. Studio mode also accepts reference/edit/extend. |
image_urls | string[] | No | First/last frames, or reference images with explicit reference/edit mode. |
image_with_roles | object[] | No | Each item: url and role (first_frame, last_frame, keyframe, middle_frame, reference_image). Do not mix image input forms. |
video_urls | string[] | No | Reference videos. For edit/extend, exactly one input video; video_url is also accepted. |
audio_urls | string[] | No | Up to three reference audio clips, each 5–30 seconds. |
audio_setting | string | No | origin or auto, for edit or reference-video mode only. |
Request example
curl --request POST 'https://aihub-admin.aimix.pro/api-platform/v1/generations' \
-H "Authorization: Bearer $PIXMIND_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "kling-v4",
"prompt": "A paper boat drifts through rainwater; stereo rainfall and soft footsteps",
"duration": 5,
"resolution": "720p",
"aspect_ratio": "9:16"
}'// Node.js 20+. Keep the API key on your server.
const apiKey = process.env.PIXMIND_API_KEY;
if (!apiKey) throw new Error("PIXMIND_API_KEY is required");
const response = await fetch("https://aihub-admin.aimix.pro/api-platform/v1/generations", {
method: "POST",
headers: {
Authorization: `Bearer ${apiKey}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"model": "kling-v4",
"prompt": "A paper boat drifts through rainwater; stereo rainfall and soft footsteps",
"duration": 5,
"resolution": "720p",
"aspect_ratio": "9:16"
}),
signal: AbortSignal.timeout(30_000)
});
const task = await response.json();
if (!response.ok || task.code !== 1000) {
throw new Error(task.message ?? task.error?.message ?? `HTTP ${response.status}`);
}
console.log(task);Accepted task response
Generation is asynchronous. Save taskId and poll GET /api-platform/v1/tasks/{taskId} until status is ready or failed.
{
"code": 1000,
"data": {
"id": "vid_44160",
"taskId": 44160,
"type": "video",
"model": "kling-v4",
"status": "processing"
}
}Query the task and retrieve results
Replace 44160 with data.taskId from the accepted response, using a key belonging to the same user. pending and processing are non-terminal; ready and failed are terminal. On ready, read images (images) or videoUrl (videos); on failed, read errorMessage. The example stops after 60 queries. If it times out, save taskId and query again later instead of creating a duplicate task. Example result URLs are placeholders.
curl 'https://aihub-admin.aimix.pro/api-platform/v1/tasks/44160' \
-H "Authorization: Bearer $PIXMIND_API_KEY"// Continue after the request example above.
const taskId = task.data?.taskId;
if (!Number.isInteger(taskId)) throw new Error("Missing numeric taskId");
async function waitForTask(taskId) {
for (let attempt = 0; attempt < 60; attempt++) {
await new Promise(resolve => setTimeout(resolve, Math.min(2000 * 1.5 ** attempt, 10000)));
const response = await fetch(`https://aihub-admin.aimix.pro/api-platform/v1/tasks/${taskId}`, {
headers: { Authorization: `Bearer ${apiKey}` },
signal: AbortSignal.timeout(30_000)
});
const result = await response.json();
if (!response.ok || result.code !== 1000) {
throw new Error(result.message ?? `HTTP ${response.status}`);
}
const data = result.data;
if (data.status === "ready") return data;
if (data.status === "failed") {
throw new Error(data.errorMessage ?? "Generation failed");
}
if (!["pending", "processing"].includes(data.status)) {
throw new Error(`Unexpected task status: ${data.status}`);
}
}
throw new Error(`Polling timed out; save taskId ${taskId} to query again later`);
}
const result = await waitForTask(taskId);
console.log(result.videoUrl);{
"code": 1000,
"data": {
"taskId": 44160,
"type": "video",
"model": "kling-v4",
"status": "ready",
"progress": 100,
"videoUrl": "https://example.com/result.mp4"
}
}