Kling 4.0 API: Pricing, Endpoints and How to Get Access

Last checked November 11, 2026 against Kling's API documentation, API updates page and API pricing page.

Short answer: Yes, the Kling 4.0 API is open. Kling's API updates page lists it as fully available since October 28, 2026, and the Kling 4.0 Flash API since November 4, 2026. The official price is 1.0 unit ($0.157) per second at 720p and 1.5 units ($0.235) per second at 1080p. A 10-second 720p clip costs about $1.57. The API outputs 3 to 30 seconds per run and does not offer 4K yet.

Kling 4.0 API at a glance

Last verified: November 11, 2026.

Is the Kling 4.0 API available now?

Yes. Kling's API updates page has two entries:

• October 28, 2026: "Kling 4.0 API Is Now Fully Available", with native output up to 30 seconds in a single run.
• November 4, 2026: "Kling 4.0 Flash API Is Now Available", with output from 3 to 20 seconds at 720p.

You need a Kling developer account, a resource package and an API key. Kling's pricing page does not list a free tier for the API.

How much does the Kling 4.0 API cost?

Kling bills the API in units, per second of video. The price depends on the model, the resolution and whether your request includes an input video.

An input video means a reference video, a video you are editing, or a video used to create a character element.

What does one clip cost?

Without an input video, you pay for the output duration:

Why does an input video change the bill?

The per-second rate drops, but the billed duration grows:

• If the input video is shorter than or equal to the output, billed duration = output duration × 2.
• If the input video is longer than the output, billed duration = input duration + output duration.

Example: a 5-second 1080p clip made from a 5-second reference video is billed as 10 seconds × 0.9 units = 9 units, about $1.41. The same clip without a reference video is 7.5 units, about $1.18.

One setting to watch: the default resolution is 1080p. If you leave it out while testing, you pay the 1080p rate. Set 720p for drafts.

Which packages can you buy?

Kling 4.0 and Kling 4.0 Flash only work with Flagship packages. The pricing page states that General packages are not compatible with them.

On November 11, 2026 the page showed discounts on these prices: 10% off a first trial purchase, and 2% to 5% off the standard packages. Units do not roll over after the validity period.

The $10 trial package holds 64 units. That is 64 seconds of Kling 4.0 at 720p, about six 10-second clips.

Which endpoints does the Kling 4.0 API have?

The base domain is https://api-singapore.klingai.com.

The text-to-video endpoint takes a prompt only. To send reference images, videos, elements or voices, use the Omni video endpoint. Our guide to Kling 4.0 Omni Reference explains what each reference type does.

How do you get access?

1. Open the Kling API platform at kling.ai/dev and sign in.
2. Buy a Flagship resource package.
3. In the developer console, create an API key. It is shown only once, so store it safely.
4. Send the key in the request header: Authorization: Bearer YOUR_API_KEY.
5. Create a task, then check its status with GET /tasks or set a callback URL.

A minimal text-to-video request looks like this:

curl --location 'https://api-singapore.klingai.com/text-to-video/kling-4.0' \
  --header 'Content-Type: application/json' \
  --header "Authorization: Bearer ${KLING_API_KEY}" \
  --data '{
    "prompt": "A man in a white shirt walks along a beach at sunset, realistic cinematic style.",
    "settings": {
      "resolution": "720p",
      "aspect_ratio": "16:9",
      "duration": 10
    }
  }'

Check the official text-to-video reference for the full field list before you ship.

What are the limits?

• Duration: 3 to 30 seconds in whole seconds. If you set no duration and the prompt names none, the default is 10 seconds.
• Resolution: 720p or 1080p. The default is 1080p.
• Aspect ratio: 21:9, 16:9, 9:16 and 1:1.
• Prompt length: up to 26,000 English characters, or up to 11,000 characters in other languages.
• References: up to 10 reference images and up to 5 reference videos, with up to 15 inputs in one task.
• Keyframes: up to 10 on Kling 4.0.
• 4K: not available in the API. See Kling 4.0 4K for the status in Kling's own app.
• Concurrency: 5 tasks at once on trial packages and 20 on standard packages. Over the limit, the API returns error code 1303. Kling states there is no separate requests-per-second limit.

Kling 4.0 API or Kling 4.0 Flash API?

Use the full model when you need more than 20 seconds, 1080p output or up to 10 keyframes. Use Flash for volume: it costs 0.6 units per second, which is 40% less than Kling 4.0 at 720p. For the model differences, see Kling 4.0 Flash.

How does the price compare with Gemini Omni 1.2 Flash?

Google lists Gemini Omni 1.2 Flash at $0.07 per second at 720p on its API. Kling 4.0 is $0.157 per second at 720p, about 2.2 times as much, and Kling 4.0 Flash is $0.094. Kling 4.0 generates up to 30 seconds per run; Gemini Omni 1.2 Flash stops at 15. The full comparison is in Kling 4.0 vs Gemini Omni 1.2 Flash.

API, MCP and CLI, or a web generator?

For the agent route, see our Kling AI MCP and CLI guide.

If you edit in Premiere Pro, After Effects or Photoshop, see our guide to the Kling plugin for Adobe apps.

If you do not write code, you can run Kling 4.0 in your browser on Kling4.tv; plans are on the Kling AI pricing page. Kling4.tv is an independent site. It is not affiliated with Kuaishou or Kling AI and does not sell API access.

FAQ

Is the Kling 4.0 API free?

No free tier is listed. The smallest package on Kling's pricing page is the Flagship Trial at a $10 list price for 64 units, valid for 30 days.

Does the Kling 4.0 API support 4K?

Not yet. The API outputs 720p and 1080p. Kling's API updates page marks 10-bit 4K as coming soon, and the price table has no 4K price for Kling 4.0.

How long can a Kling 4.0 API video be?

3 to 30 seconds in a single run on Kling 4.0, and 3 to 20 seconds on Kling 4.0 Flash.

Can I use an older Kling API package for Kling 4.0?

No. Kling's pricing page says General packages are not compatible with Kling 4.0 or Kling 4.0 Flash. You need a Flagship package.

How much is a 30-second Kling 4.0 video on the API?

30 units at 720p, about $4.71, or 45 units at 1080p, about $7.07, when the request has no input video.

Where do these facts come from?

• API Updates, Kling AI. Availability dates for Kling 4.0 and Kling 4.0 Flash, request paths, resolutions, input limits.
• Video API pricing, Kling AI. Unit prices per second and the input-video billing rule.
• API packages, Kling AI. Flagship package prices, units, validity and concurrency.
• Kling 4.0 text to video reference, Kling AI. Request fields, defaults, prompt length and task query.
• Concurrency rules, Kling AI. Concurrency behavior and error code 1303.

All facts were checked on November 11, 2026. Prices and limits change, so confirm them on Kling's pages before you budget.

Try Kling AI Today

No API key needed: write a prompt, check the credit estimate and generate a Kling 4.0 video in your browser.

Open the Kling 4.0 generator