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Kling 4.0 Flash Is Now Open to Everyone: Faster AI Video at $0.094 a Second
Kling 4.0 Flash is now available to everyone on the Kling website and via API. The faster, cheaper tier of Kuaishou's Kling 4.0 video model opened to all users on November 4, after a limited early access for Ultra Yearly subscribers that began on September 28. It generates clips of 3 to 20 seconds at 720p, with stereo sound built in, for $0.094 a second on the API.
Flash is the tier for frequent creation: faster generation, lower cost, narrower specs. The full Kling 4.0 model is the one for long takes and higher resolutions. The two are easy to confuse, and much of the coverage this week confuses them, so this article starts by separating them.
Flash versus the full model: read this first
The 30-second clips belong to the full Kling 4.0, not to Flash. The full model, which launched globally on October 15 after being announced on September 28, generates native clips of up to 30 seconds in one pass, at 720p, 1080p or 4K, with 10-bit HDR at 1080p and 4K. Flash is capped at 20 seconds and 720p only, with 8-bit SDR output. On the API, Flash costs 10 credits a second, against 17 for the full model at 720p, which works out to $0.094 a second for Flash and $0.157 for the full model.
Both tiers share the same four modes, text-to-video, image-to-video, Omni Reference and video edit, and both take the same references: up to 10 images, 5 clips and 7 elements, plus a start frame. Flash has no end frame, no multi-shot prompts and no element voices; step up to the full model for those. A 5-second Flash clip costs 50 credits, a 20-second clip 200.
What the full Kling 4.0 does
Kling announced Kling 4.0 on September 28 and launched it globally on October 15, framing the upgrade around realism, control and professional quality. The full model supports up to 30 seconds in a single generation, adjustable in one-second steps, with up to 10 keyframes to steer a shot like a storyboard, up to 15 combined Omni Reference assets, stereo audio, and targeted editing. Kling also documents MCP and CLI integrations for automated creation, and a two-minute video extension is listed as an upcoming feature.
The full model is the one creators reach for when a single take has to carry a scene. Flash is the one they reach for when they are iterating: shorter clips, lower cost, faster turnaround, same references and the same sound.
Who Flash is for
Flash is built for frequent creation, and the pricing shows it. At $0.094 a second it is the cheapest 720p video per second among the current flagship models: Gemini Omni Flash sits at about $0.10, and the full Kling 4.0 at $0.157. That ranking flips if you need length, since Flash stops at 20 seconds, or resolution, since it stops at 720p. For drafts, tests, social clips and anything you will regenerate five times before keeping one, Flash is the right tier. For the keeper, step up.
The comparison that matters
The honest comparison is with Google's Gemini Omni 1.2 Flash, which went generally available on November 5 at $0.07 a second for 720p, with clips up to 15 seconds. Omni 1.2 is cheaper per second, but Flash gives you 20 seconds against Omni's 15, and Kling's reference system, up to 15 assets and 10 keyframes on the full model, is built for steering a shot rather than editing one after the fact. Neither model has independent benchmark results yet; the specs and prices come from the vendors' own pages. Choose Flash when you need cheap, fast iterations at 720p, and the full Kling 4.0 when a single 30-second take is the point.
How to use Flash, and what to watch
On the Kling website, Flash sits alongside the full model as a faster option in the creation flow. Through the API, it is listed as video.kling_v4_flash, and it takes the same references as the full model: up to 10 images, 5 clips and 7 elements, plus a start frame. The model list in the API always shows the current tiers, so check it before building a pipeline around a specific model ID, since Kling has changed availability twice in two months.
Two things are worth watching. The first is the two-minute video extension Kling lists as upcoming for the full model, which would turn a 30-second take into a much longer sequence and change what the model is useful for. The second is 10-bit HDR, which the full model already offers at 1080p and 4K and Flash does not. If your output is going to a client screen rather than a social feed, that gap alone justifies the step up, whatever the per-second price says.