Kling 4.0 is Kuaishou's fourth-generation video generation model available through the reAPI platform. It helps developers and video creators produce high-fidelity clips ranging from 3 to 30 seconds with integrated stereo sound. The model is built for users who need longer single-take shots and precise control over motion using keyframes and multi-modal references.
Developers can integrate this model to build automated video workflows, while creators use it to bypass the technical hurdles of traditional animation. It handles complex tasks like lip-syncing and material consistency across fast cuts. Because it runs on a credit-based API, you only pay for the videos that successfully complete, making it easier to manage costs during production.
Key features
- Generates single continuous clips up to 30 seconds long
- Supports both 720p and 1080p high-definition output resolutions
- Includes automatic stereo sound generation for every MP4 file
- Accepts up to 8 intermediate keyframes to control specific motion paths
- Handles up to 15 reference files including images, videos, and audio
- Provides dedicated modes for editing existing footage or extending clips
- Uses a credit-based pricing model where 1 credit equals $0.001 USD
How to use
- Sign up for a reAPI account and generate a Bearer key in the dashboard settings.
- Add credits to your balance to cover the generation costs of your first project.
- Test your prompts and reference media in the web-based playground to find the right settings.
- Copy the request parameters and model ID kling-4-0 into your application code.
- Send a POST request to the video generations endpoint and store the returned task ID.
- Poll the task status until it finishes and download the final MP4 video.
Use cases
- A continuous 30-second walk-through of a Japanese neighborhood generated from a single text prompt.
- Adding accurate lip-syncing to digital characters in a 15-second cinematic dialogue scene.
- Maintaining consistent material looks, like origami paper or cake textures, through fast action sequences.
- Extending a short video clip by generating new content that starts from its final frame.
Pricing
Kling 4.0 uses a credit-based system where 1 credit is $0.001 USD. A 5-second sample at the 720p tier costs approximately $0.713. Costs vary based on resolution and whether you are using text-to-video or video-reference modes.
FAQ
What is Kling 4.0?
Kling 4.0 is a video generation model from Kuaishou that creates high-definition clips with sound from text, images, or video inputs.
Is Kling 4.0 free?
No, it operates on a pay-per-generation basis, though new reAPI accounts typically receive a small starting credit for initial testing.
What is the maximum video length?
The model can generate a single continuous clip up to 30 seconds long, which is double the limit of the previous version.
Can I edit existing videos?
Yes, the model includes an edit mode that allows you to change the setting, season, or style of an existing video file.
Does it support 4K resolution?
No, Kling 4.0 currently supports 720p and 1080p, while the Kling 3.0 model is still used for 4K requirements.
What file format does it output?
All generated videos are delivered as MP4 files and include a stereo audio track.
