Kling 4.0 API
Kling 4.0 combines multimodal video generation, reference-based creation and editing, with a full model and a faster Flash variant.
Kling 4.0 Flash API
kuaishou/kling-4.0-flash
Faster Kling 4.0 variant for short-form creation: 3–20-second video, 720p, 8-bit SDR and Omni Reference. Multiple keyframes and start-and-last frames are not supported. Public API model ID and pricing are unconfirmed.
Kling 4.0 API Background
Overview
Kling 4.0 is Kuaishou’s multimodal video creation family, comprising the full Kling 4.0 model and the lighter Kling 4.0 Flash. It combines video generation, visual references and editing.
Development History
Kuaishou confirms Kling 4.0 launched on October 15, 2026. Flash early access began on September 28. Product availability does not establish public developer API availability. As checked on October 25, official public API model IDs and prices have not been verified.
Key Innovations
- More stable complex motion and camera work.
- Native generation up to 30 seconds in the full model.
- Omni Reference and timeline keyframes for creative control.
Kling 4.0 API Technical Specifications
Architecture
A native multimodal video generation family. No parameter count or detailed network architecture is asserted. Local catalog identifiers kling-4.0 and kling-4.0-flash are not verified upstream API model IDs.
Parameters
Full model: 3–30-second generation at 720p, 1080p or 4K; aspect ratios 21:9, 16:9, 1:1, 9:16 and Auto. Flash: 3–20 seconds, 720p, 8-bit SDR. Text prompts support up to 8,000 tokens; this is a prompt limit, not an LLM context window.
Capabilities
- Text-to-video, image-to-video and Omni Reference.
- Full model supports first/last frames and up to 10 keyframe images.
- Full-model reference limits: 15 assets combined, with up to 10 images, 5 videos totaling 30 seconds and 7 subjects; individual maxima cannot all be added together.
- Full model supports two-channel stereo, lip-sync, multilingual speech and on-screen text.
- Full-model editing accepts up to 5 clips including a primary video, with 30 seconds total.
Limitations
- Flash does not currently support start-and-last frames or multiple keyframes.
- 10-bit HDR at 1080p/4K and repeated extension to two minutes are still marked coming soon in official guides.
- MCP and CLI integration is announced, while developer API access and pricing require separate confirmation.
- Creation modes and limits depend on the actual product interface; Omni Reference and Keyframes are separate entry points.
Kling 4.0 API Performance
Strengths
- Designed for stable action, tracking and orbit shots.
- Reference controls help preserve characters and product appearance.
- Keyframes support planned story beats in the full model.
Real-world Effectiveness
Suitable for ads, storyboards and short narrative sequences. These are vendor-described capabilities, not independently measured guarantees. Flash prioritizes faster iteration; no numerical generation-time guarantee is asserted.
Kling 4.0 API When to Use
Scenarios
- Choose full Kling 4.0 for longer scenes, high resolution and precise keyframe control.
- Choose Flash for rapid short-form drafts at 720p.
- Use references and targeted edits to create product and campaign variations.
Best Practices
- Assign each reference a clear role: identity, scene, motion, style or pacing.
- Review motion, continuity, dialogue and brand text over the complete video.
- Check feature availability before planning HDR or two-minute extension workflows.
- Official sources: https://kling.ai/quickstart/kling-4-model-user-guide ; https://kling.ai/dev/model-release/kling-4 ; https://ir.kuaishou.com/news-releases/news-release-details/kling-ai-officially-launches-next-generation-kling-40-raising .