Kling 4.0 Text to Video

kwaivgi/kling-v4.0/text-to-video

Generate 3–30 second videos from a prompt with synchronized audio, in 720p or 1080p.

Examples

Kling 4.0 Text to Video Examples 1

Parameters

NameTypeDefaultConstraintsDescription
prompt *Prompttextarea—≤ 5000 charsThe positive prompt for the generation.
resolutionResolutionselect720p720p | 1080pOutput resolution.
durationDurationselect53 ~ 30 · step 1 · 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | …The duration of the generated video in seconds (3-30).
aspect_ratioAspect ratioselect16:916:9 | 9:16 | 1:1 | 21:9Output video aspect ratio.

Output fields

FieldTypeDescription
videosarray<string>Generated video URLs.

API

Call this model through one unified REST API. Get a key on the API Keys page.

cURL
# 1) Submit — returns { "task_uuid": "..." }
curl -X POST "https://www.namifusion.com/api/v1/marketplace/run/kwaivgi/kling-v4.0/text-to-video" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "input": {
    "prompt": "A cinematic portrait, dramatic rim light, shallow depth of field",
    "resolution": "720p",
    "duration": 5,
    "aspect_ratio": "16:9"
  }
}'

# 2) Poll until status is "completed", then read the output URLs
curl "https://www.namifusion.com/api/v1/marketplace/run/tasks/TASK_UUID" \
  -H "Authorization: Bearer YOUR_API_KEY"
Python
import time, requests

API_KEY = "YOUR_API_KEY"
HEADERS = {"Authorization": f"Bearer {API_KEY}"}

# 1) Submit
resp = requests.post(
    "https://www.namifusion.com/api/v1/marketplace/run/kwaivgi/kling-v4.0/text-to-video",
    headers=HEADERS,
    json={
        "input": {
            "prompt": "A cinematic portrait, dramatic rim light, shallow depth of field",
            "resolution": "720p",
            "duration": 5,
            "aspect_ratio": "16:9"
        }
    },
)
resp.raise_for_status()  # 401/402/429/5xx stop here instead of polling a bad task
task = resp.json()

# 2) Poll until a terminal state (completed / failed / cancelled).
#    This model is allowed up to 1800s server-side.
deadline = time.time() + 1860
while task.get("status") not in ("completed", "failed", "cancelled"):
    if time.time() > deadline:
        raise TimeoutError(f"still {task.get('status')} — keep the task_uuid and poll later")
    time.sleep(3)
    poll = requests.get(f"https://www.namifusion.com/api/v1/marketplace/run/tasks/{task['task_uuid']}", headers=HEADERS)
    poll.raise_for_status()
    task = poll.json()

print(task["status"], task.get("output"))
JavaScript
const API_KEY = "YOUR_API_KEY";
const HEADERS = { Authorization: `Bearer ${API_KEY}` };

// 1) Submit
const resp = await fetch("https://www.namifusion.com/api/v1/marketplace/run/kwaivgi/kling-v4.0/text-to-video", {
  method: "POST",
  headers: { ...HEADERS, "Content-Type": "application/json" },
  body: JSON.stringify({
    "input": {
      "prompt": "A cinematic portrait, dramatic rim light, shallow depth of field",
      "resolution": "720p",
      "duration": 5,
      "aspect_ratio": "16:9"
    }
  }),
});
if (!resp.ok) throw new Error(`submit failed: ${resp.status} ${await resp.text()}`);
let task = await resp.json();

// 2) Poll until a terminal state (completed / failed / cancelled).
//    This model is allowed up to 1800s server-side.
const deadline = Date.now() + 1860 * 1000;
while (!["completed", "failed", "cancelled"].includes(task.status)) {
  if (Date.now() > deadline) throw new Error(`still ${task.status} — keep the task_uuid and poll later`);
  await new Promise((r) => setTimeout(r, 3000));
  const poll = await fetch(`https://www.namifusion.com/api/v1/marketplace/run/tasks/${task.task_uuid}`, { headers: HEADERS });
  if (!poll.ok) throw new Error(`poll failed: ${poll.status}`);
  task = await poll.json();
}

console.log(task.status, task.output);

Documentation

Kling 4.0 · Text to Video

Generate a 3–30 second video from a text prompt, with synchronized stereo audio. Describe subjects, action, camera movement and desired sound in the prompt.

Inputs

  • prompt: string, required.
  • resolution: "720p" (default) or "1080p".
  • duration: integer from 3 through 30, default 5.
  • aspect_ratio: "16:9" (default), "9:16", "1:1" or "21:9".

Limits and references

No image, video or audio-reference input is supported on this endpoint. Native audio is included; there is no sound switch.

List price and initial credit charge

720p: $0.157 per output second. 1080p: $0.235 per output second.

Cost = output seconds × resolution rate. A 5-second clip costs $0.785 at 720p or $1.175 at 1080p.

1 USD = 100 Nami credits. Round the total charge upward to 0.01 credit: credits = ceil(cost_usd × 10000) / 100. These are list prices; no promotional discount is applied.

MaaS mapping

prompt, resolution, duration and aspect_ratio pass to MaaS with the same names and types.

Nami API

Send a POST request with Authorization: Bearer YOUR_NAMI_API_KEY and Content-Type: application/json to:

https://www.namifusion.com/api/v1/marketplace/run/kwaivgi/kling-v4.0/text-to-video

Example request body:

{
  "input": {
    "prompt": "A small sailboat crosses a quiet lake at sunrise. Slow lateral tracking shot, gentle water sounds and distant birds.",
    "resolution": "720p",
    "duration": 5,
    "aspect_ratio": "16:9"
  }
}

Replace example.com URLs with publicly accessible media URLs. Use the returned task_uuid to poll GET https://www.namifusion.com/api/v1/marketplace/run/tasks/{task_uuid} with the same authorization. On success, read generated video URLs from output.videos.

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