What it is
Kling 4.0 is Kuaishou's latest video generation model, launched on October 15, 2026, after a faster Kling 4.0 Flash went to a limited early-access group on September 28. Kling's site has moved from klingai.com to kling.ai. The model generates 3 to 30 second clips with two-channel stereo audio, takes prompts of up to 8,000 tokens, and accepts up to 10 keyframes and up to 15 references in one request (up to 10 images, 5 videos and 7 elements, plus a voice).
It also edits existing footage, taking one primary clip and up to four supporting clips within a 30-second total, and adds a 21:9 aspect ratio. Sources disagree on what ships today: fal lists 720p, 1080p and 4K output with 10-bit HDR still coming, while Kuaishou's announcement, as reported by MarketScreener, describes HDR as available and 4K as a future addition. Flash is 720p and 8-bit only.
For now Kling 4.0 is reached through the Kling app and Kling's MCP server and command-line tool. fal shows Kling 4.0 in its playground but says API access is coming soon, and no per-second API price has been published.
Our review
Kling 4.0 is a specification without a scorecard. Ten keyframes, fifteen references and 30-second takes put it ahead of most rivals on control, but it has not appeared on Artificial Analysis's text-to-video board, and the developer API is still listed as coming soon. Anyone choosing a model for a pipeline is being asked to take Kuaishou's word for it.
The starting point is not flattering. Its predecessor, Kling 3.0 Pro at 1080p, is the anchor of Artificial Analysis's board, fixed at 1000 Elo and ranked 18th, while Wan 3.0 leads at 1175 and Seedance 2.5 sits at 1158. Kling 3.0 Omni does a little better at 1020. To matter to quality-first buyers, 4.0 has to close a gap of roughly 150 points, which would be a large jump for one release.
The control features are aimed at ad and brand work. Creative recreation keeps the pacing and framing of an existing video while swapping the product or presenter, and depth-map and white-model videos can steer motion. The catch is the 30-second ceiling on all input video combined: with one supporting clip, fal notes the primary clip can run to 27 seconds at most, which rules out re-cutting anything longer than a short spot.
Cost is a guess until the API opens. On fal, Kling O3 Pro with audio costs $0.14 a second and its 4K tier $0.42, so a single 30-second 4K take on the old model is about $12.60. If 4.0 lands near those rates it will undercut Seedance 2.5's $34 a minute at 1080p, but it will need to win on quality to justify a switch from Wan 3.0 at $12.
Where it earns its place
A brand studio producing 15 to 30 second social spots for a consumer electronics client
Re-shoot an existing ad with a new product without booking a set
Feed the old spot as a reference and use creative recreation to keep its pacing while swapping the product. Done in the Kling app on a subscription for now; budget is unknown at API scale because Kling has not priced 4.0.
A previsualisation artist on a small film crew
Turn a storyboard of 8 to 10 frames into one continuous animatic
Load the boards as keyframes and generate a single 30-second take, instead of stitching five short clips. Kling 4.0 Flash is quicker for drafts but outputs 720p and 8-bit only.
A developer building an agent that drafts video for a marketing team
Call a video model from an agent workflow without writing a REST client
Kling's MCP server exposes Omni Reference and keyframe-to-video to agents today. There is no published rate limit or price, so it suits internal prototypes rather than a customer-facing product.
Before you commit
- Setup
- Sign in to the Kling app at kling.ai or connect Kling's MCP server or CLI; fal shows Kling 4.0 in its playground but has not opened API calls.
- Integrations
- Kling MCP server and CLI for agents; fal has listed text-to-video, image-to-video, reference-to-video and video edit endpoints for when the API opens.
- Data and privacy
- Kling's retention and training terms for uploaded references were not available on the pages we could reach; treat uploaded footage and voice samples as leaving your control until you have them in writing.
- Cost at scale
- Not published for 4.0. As a guide, the predecessor Kling O3 costs $0.14 a second with audio and $0.42 a second at 4K on fal, so 100 thirty-second 4K takes a month would be about $1,260 at the old rate.
- Limits
- Clips of 3 to 30 seconds (Flash 3 to 20); edits take up to 5 clips totalling 30 seconds; video extension to 2 minutes is announced but not live; HDR and 4K availability is reported inconsistently.
What's good
- Up to 10 keyframes and 15 mixed references per request
- 30-second single takes with stereo audio and an 8,000-token prompt
- Edits existing footage, including swapping products or characters
What's not
- No open API and no published per-second price
- Not yet on Artificial Analysis or other blind-vote boards
- All input video for edits capped at 30 seconds combined
Best for
Creative teams already in the Kling app who want long, keyframe-directed shots and can wait for an API.
Alternatives
Kling 4.0: common questions
- Is Kling 4.0 worth it?
- Kling 4.0 has the longest spec sheet in video generation and, so far, nothing independent to back it up. We rate it 4.1 out of 5.
- How much does Kling 4.0 cost?
- Kling app subscriptions; Kling 4.0 API pricing not published. Predecessor Kling O3 on fal costs $0.14 a second (Pro, with audio) and $0.42 a second at 4K.
- What are the downsides of Kling 4.0?
- No open API and no published per-second price; not yet on Artificial Analysis or other blind-vote boards; all input video for edits capped at 30 seconds combined.
- Who is Kling 4.0 best for?
- Creative teams already in the Kling app who want long, keyframe-directed shots and can wait for an API.
- How much does Kling 4.0 cost for a team or in production?
- Not published for 4.0. As a guide, the predecessor Kling O3 costs $0.14 a second with audio and $0.42 a second at 4K on fal, so 100 thirty-second 4K takes a month would be about $1,260 at the old rate.
- Is Kling 4.0 safe for company data?
- Kling's retention and training terms for uploaded references were not available on the pages we could reach; treat uploaded footage and voice samples as leaving your control until you have them in writing.
- What are the best Kling 4.0 alternatives?
- The closest alternatives we have reviewed are Seedance 2.5, Wan 3.0, Luma Ray3.2 and Runway Gen-4.5.
Answers checked Oct 23, 2026.
Make Kling 4.0? Show this rating on your site
