Kling 4.0 Flash API

Name: Kling 4.0 Flash API - Example AI Video
Uploaded: 2026-11-05
Description: Sample video generated with the Kling 4.0 Flash API on VideoGenAPI

Interactive demo

Try Kling 4.0 Flash right now

Explore the interface and see how easy it is to generate videos with Kling 4.0 Flash. Create an account and pick a plan to start generating.

Playground Demo - Kling 4.0 Flash

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Generation Type

Video Settings

Sign up to generate videos

Create a free account to access the full playground and generate videos with Kling 4.0 Flash on a monthly plan.

timer ~65s generation

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Demo Mode

Kling 4.0 Flash

by Kuaishou

Kling 4.0 Flash by Kuaishou: the fast tier of Kling 4.0, text-to-video and image-to-video with stereo audio, 3 to 20 seconds at 720p. Billed per second from your balance: $0.15/s.

720p • 3-20s • ~65s processing

Gallery

Kling 4.0 Flash examples

Discover what's possible with Kling 4.0 Flash AI video generation

A dancer in a red dress crosses a rain-soaked plaza at night, spins under a street lamp and looks into the camera, steady tracking shot, reflections on wet stone

Generated with the Kling 4.0 Flash API at up to 720p. Results vary with prompt detail and requested duration.

What is the Kling 4.0 Flash API?

The Kling 4.0 Flash API is a REST interface that lets developers generate AI videos programmatically using Kuaishou's Kling 4.0 Flash model. It supports text-to-video, image-to-video through a single POST endpoint. VideoGenAPI handles authentication, billing, and provider infrastructure - you only need one API key to start building with the Kling 4.0 Flash API.

Kuaishou

Provider

REST

API protocol

~65s

Avg. generation

How to use the Kling 4.0 Flash API

Integrate the Kling 4.0 Flash API in your app in under 5 minutes with these four steps.

1

Create your VideoGenAPI account

Sign up free at VideoGenAPI.com and generate your API key from the dashboard. No Kuaishou account needed.
2

Send a request to the Kling 4.0 Flash API

POST to https://videogenapi.com/api/v1/generate with your API key, model "kling-4-flash", and a text prompt describing your video.
3

Poll for completion

Use the returned generation_id to poll GET /api/v1/status/{id} until the job completes. Video completion webhooks are not available yet.
4

Download your video

Once status is "completed", retrieve the video URL from the response and embed it in your app, website, or workflow.

Get your Kling 4.0 Flash API key

Documentation

About Kling 4.0 Flash

info Overview

Kling 4.0 Flash is the lighter, faster tier of Kuaishou's Kling 4.0. It opened to Kling Ultra subscribers on September 28, 2026, two weeks before the full model. It keeps the Kling 4.0 look and motion but trades resolution and length for speed: 3 to 20 seconds at 720p, typically rendered in about a minute for a 5-second clip. On VideoGenAPI it is a draft-and-iterate model: try prompts and timings with Flash at $0.15 per second, then switch the model key to kling-4 (/kling-4-api) for the 1080p, up-to-30-second final render. It supports text-to-video in four aspect ratios and image-to-video from a start frame, where the output follows the frame's proportions. Failed generations are refunded to your balance.

stars Key Strengths

check_circle About a minute to render a 5-second clip, with stereo audio
check_circle 3 to 20 second clips at 720p
check_circle Text-to-video in 16:9, 9:16, 1:1 or 21:9
check_circle Image-to-video from a start frame
check_circle $0.15 per second, refunded if a generation fails

check_circle Supported Features

Text to Video
Image to Video

settings Specifications

Max Resolution: 720p
Duration Range: 3-20s
Avg. Processing: ~65s

workspace_premium Why Kling 4.0 Flash via VideoGenAPI?

check_circle
Unified API: Access Kling 4.0 Flash alongside 18 other models with one API key - no separate Kuaishou setup.
check_circle
Per-second pricing: $0.15 per second at 720p, from your balance on top of a monthly plan. Failed generations are refunded.
check_circle
Production-ready: one REST endpoint, status polling, an MCP server for AI agents, and full docs.

Use cases

What you can build with Kling 4.0 Flash

1

Prompt iteration

Explore wording, camera moves and timing cheaply before a full Kling 4.0 render.

2

Social video at volume

720p vertical or square clips for feeds, generated fast enough for interactive tools.

3

Animated stills

Bring a product shot or illustration to life from a single start frame.

API reference

Kling 4.0 Flash API documentation

Quick start guide to integrate Kling 4.0 Flash in your application

code Endpoint

POST https://videogenapi.com/api/v1/generate

tune Kling 4.0 Flash API parameters

Request parameters accepted by the Kling 4.0 Flash API on POST /api/v1/generate
Parameter	Type	Required	Kling 4.0 Flash values
model	string	Yes	`"kling-4-flash"`
prompt	string	Yes	Scene description, up to 1,000 characters.
image_url	string	No	Public jpg, png, gif or webp URL. Animates the image (image-to-video).
duration	integer	No	3 to 20 seconds, up to 15s on every plan.
resolution	string	No	720p.
aspect_ratio	string	No	16:9, 4:3, 1:1 or 9:16 (text-to-video).
seed	integer	No	Fixed value for reproducible output, -1 for random.
add_audio	boolean	No	Kling 4.0 Flash generates native audio with the video.

Average generation time: ~65s. Poll GET /api/v1/status/{id} with the returned generation_id. Full reference: /docs/generate.

send Request Example

{
  "model": "kling-4-flash",
  "prompt": "A dancer in a red dress crosses a rain-soaked plaza at night, spins under a street lamp and looks into the camera, steady tracking shot, reflections on wet stone",
  "duration": 10,
  "resolution": "720p"
}

download Response Example

{
  "success": true,
  "generation_id": "gen_abc123xyz",
  "status": "in_progress",
  "estimated_time": 65}

integration_instructions Code Examples

const response = await fetch('https://videogenapi.com/api/v1/generate', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': 'Bearer YOUR_API_KEY'
  },
  body: JSON.stringify({
    model: 'kling-4-flash',
    prompt: 'A dancer in a red dress crosses a rain-soaked plaza at night, spins under a street lamp and looks into the camera, steady tracking shot, reflections on wet stone',
    duration: 10  })
});

const data = await response.json();
console.log(data.generation_id);

import requests

response = requests.post(
    'https://videogenapi.com/api/v1/generate',
    headers={
        'Content-Type': 'application/json',
        'Authorization': 'Bearer YOUR_API_KEY'
    },
    json={
        'model': 'kling-4-flash',
        'prompt': 'A dancer in a red dress crosses a rain-soaked plaza at night, spins under a street lamp and looks into the camera, steady tracking shot, reflections on wet stone',
        'duration': 10    }
)

data = response.json()
print(data['generation_id'])

$ch = curl_init('https://videogenapi.com/api/v1/generate');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Content-Type: application/json',
    'Authorization: Bearer YOUR_API_KEY'
]);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode([
    'model' => 'kling-4-flash',
    'prompt' => 'A dancer in a red dress crosses a rain-soaked plaza at night, spins under a street lamp and looks into the camera, steady tracking shot, reflections on wet stone',
    'duration' => 10]));

$response = curl_exec($ch);
$data = json_decode($response, true);
echo $data['generation_id'];

curl -X POST https://videogenapi.com/api/v1/generate \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "kling-4-flash",
    "prompt": "A dancer in a red dress crosses a rain-soaked plaza at night, spins under a street lamp and looks into the camera, steady tracking shot, reflections on wet stone",
    "duration": 10  }'

Kling 4.0 Flash image-to-video request

curl -X POST https://videogenapi.com/api/v1/generate \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "kling-4-flash",
    "prompt": "Slow push in, soft natural light, subtle movement",
    "image_url": "https://example.com/your-image.jpg",
    "duration": 5
  }'

View Full Documentation arrow_forward

Pricing

Kling 4.0 Flash API pricing

Kling 4.0 Flash is billed per video, not per second of output. See the cost calculator for your volume.

$0.15/s

per second of video at 720p via the Kling 4.0 Flash API

check_circle One API key for Kling 4.0 Flash and 18 other models
check_circle No Kuaishou account required
check_circle Billed per video, never per second of output

Start with the Kling 4.0 Flash API

Comparison

Kling 4.0 Flash API vs alternatives

How the Kling 4.0 Flash API compares on resolution, clip length, generation speed and price. All models below share one API key.

Comparison of the Kling 4.0 Flash API against alternative AI video generation models on VideoGenAPI
Model	Provider	Max resolution	Clip length	Avg. speed	Price / video
Kling 4.0 Flash API This page	Kuaishou	720p	3-20s	~65s	$0.15/s
Kling 4.0 API	Kuaishou	1080p	3-30s	~150s	$0.25/s
Kling 3.0 API	Kuaishou	1080p	5-10s	~250s	Included, from $0.011
Wan 3.0 API	Alibaba	1080p	2-30s	~150s	$0.10/s

Switching between these models means changing the kling-4-flash value in your request body. The endpoint, authentication and status polling stay the same.

Limits

Kling 4.0 Flash API limitations

Plan duration and resolution caps apply even when the model supports higher output. See pricing.
Jobs are asynchronous: poll GET /api/v1/status/{id}. Video completion webhooks are not available yet.
Rate limits and fair-use throttling are documented on /docs/rate-limits.
Prompts and images that violate the content guidelines are rejected.
This model is billed per generation on top of the monthly plan ($0.75/video).

Text-to-video API hub Image-to-video API hub Catalogue benchmark Generate endpoint docs

Reviewed by Enzo Lanne · Founder, VideoGenAPI · Updated 5 November 2026

FAQ

Kling 4.0 Flash API questions

How do I call Kling 4.0 Flash on VideoGenAPI? expand_more

Send POST /api/v1/generate with "model": "kling-4-flash", a prompt and a duration from 3 to 20 seconds. Add "image_url" to animate a start frame. Output is 720p.

How much does Kling 4.0 Flash cost? expand_more

$0.15 per second of output from your balance, so a 10-second clip costs $1.50. Failed generations are refunded automatically.

How fast is Kling 4.0 Flash? expand_more

In our tests a 5-second 720p clip rendered in about 65 seconds. Longer clips take proportionally longer.

Can Kling 4.0 Flash use an end frame or 1080p? expand_more

No. Flash is 720p only and takes a start frame without an end frame. Use Kling 4.0 (/kling-4-api) for 1080p, clips up to 30 seconds and end frames.

How much does one Kling 4.0 Flash API video cost? expand_more

Kling 4.0 Flash is billed per second of output from your VideoGenAPI balance: $0.15 per second at 720p, so a 10-second 720p clip costs $1.50. You need a monthly plan (from $29) for API access; failed generations are refunded to your balance.

Related models

Compare with other AI video models

Explore alternative models for different quality, speed, and budget needs.

Kling 4.0 API

Kuaishou

Kling 4.0 by Kuaishou: text-to-video and image-to-video with stereo audio, 3 to 30 seconds at 720p or 1080p, with an optional end frame. Billed per second from your balance: $0.25/s at 720p, $0.35/s at 1080p.

Kling 4.0 API docs arrow_forward

Kling 3.0 API

Kuaishou

Kling 3: Top-tier text-to-video generation with unparalleled motion fluidity, cinematic visuals, and exceptional prompt precision.

Kling 3.0 API docs arrow_forward

Wan 3.0 API

Alibaba

Wan 3.0 by Alibaba: text-to-video and image-to-video with native audio, 2 to 30 seconds at 480p, 720p or 1080p. Billed per second from your balance: $0.10/s at 480p, $0.20/s at 720p, $0.40/s at 1080p.

Wan 3.0 API docs arrow_forward

Try Kling 4.0 Flash right now

Demo Preview

Kling 4.0 Flash examples

What is the Kling 4.0 Flash API?

How to use the Kling 4.0 Flash API

Create your VideoGenAPI account

Send a request to the Kling 4.0 Flash API

Poll for completion

Download your video

About Kling 4.0 Flash

info Overview

stars Key Strengths

check_circle Supported Features

settings Specifications

workspace_premium Why Kling 4.0 Flash via VideoGenAPI?

What you can build with Kling 4.0 Flash

Prompt iteration

Social video at volume

Animated stills

Kling 4.0 Flash API documentation

code Endpoint

tune Kling 4.0 Flash API parameters

send Request Example

download Response Example

integration_instructions Code Examples

Kling 4.0 Flash image-to-video request

Kling 4.0 Flash API pricing

Kling 4.0 Flash API vs alternatives

Kling 4.0 Flash API limitations

Kling 4.0 Flash API questions

Compare with other AI video models

Kling 4.0 API

Kling 3.0 API

Wan 3.0 API

Ready to ship with Kling 4.0 Flash?