Kling 4.0 vs Seedance 2.5: How to Choose for Commercial Video

Seedance 2.5 has become the default choice for many commercial video teams: ads, e-commerce product clips, and short drama. Kling 4.0 is now live on WaveSpeedAI and competes for the same work, so the practical question is which one fits a given job.

This is a buyer’s guide, not a benchmark. We have not run head-to-head quality tests, so we do not claim that either model produces better video. Instead it compares what is visible in the specs: duration ceilings, reference inputs, resolution options, edit and extend endpoints, and how each is priced. Start from the Kling 4.0 API page or the Seedance 2.5 API page, or try both in the Video Generator.

Quick answer

Pick Seedance 2.5 when you need output above 1080p (up to 4K), a large reference set (up to 30 reference images), or extra aspect ratios such as 4:3 and 3:4.
Pick Kling 4.0 when your brief is driven by reference videos and audio (up to 5 videos and 3 audios, alongside up to 10 images), when you want to steer a clip from a first frame toward a last frame with keyframes in between, or when per-second pricing at 720p and 1080p suits your budget.
Both reach 30 seconds per clip, generate native audio, and have dedicated edit and extend endpoints, so neither choice gives up those workflows.
Kling 3.0 and O3 remain available as the previous Kling generation, for multi-shot prompts and Kling Elements.

Specs side by side

Seedance 2.5 and Kling 3.0 columns reflect live model parameters on WaveSpeedAI. The Kling 4.0 column reflects its WaveSpeedAI model pages at the time of writing.

	Seedance 2.5	Kling 4.0	Kling 3.0 / O3 (previous generation)
Clip length	4 to 30 seconds	3 to 30 seconds (whole seconds, default 5)	3 to 15 seconds
Resolution	480p, 720p, 1080p, 4K	720p (default), 1080p	Standard, Pro, and native 4K tiers
Aspect ratios	16:9, 9:16, 4:3, 3:4, 1:1, 21:9	16:9, 9:16, 1:1, 21:9	16:9, 9:16, 1:1
Native audio	Yes (`generate_audio`)	Yes, synchronized stereo audio generated with the picture	Yes (`sound`) on Standard, Pro, 4K
References	Up to 30 reference images, plus reference video and audio	Up to 10 images, 5 videos and 3 audios (15 files at most)	Up to 3 Kling Elements (3.0 image-to-video and O3); O3 reference-to-video adds up to 7 images and a video
Frame control	Prompt and reference driven	First frame, optional last frame, and keyframes (up to 10 images in total)	Image-to-video
Multi-shot in one request	Prompt-driven	Prompt-driven	Up to 6 shots via `multi_prompt`
Editing	Dedicated video-edit endpoint	Dedicated video-edit endpoint	O3 video-edit endpoint
Extension	Dedicated video-extend endpoint	Dedicated video-extend endpoint	Not a separate endpoint
Fast tier	Seedance 2.5 Turbo (720p, 1080p)	None	Kling 3.0 Turbo

Where the specs favor Seedance 2.5

Resolution above 1080p

Seedance 2.5 can output 4K, while Kling 4.0 on WaveSpeedAI stops at 1080p. If a deliverable needs a native 4K master, that decides it, unless you use the 4K tiers of Kling 3.0 or O3.

Reference-heavy briefs with many images

Commercial work usually comes with assets: product photos from several angles, a brand character, a location. Seedance 2.5 accepts up to 30 reference images alongside reference video and audio, which leaves room for a full product set in one request. Kling 4.0 caps reference images at 10.

Aspect ratio coverage

Six aspect ratios, including 4:3 and 3:4, map directly onto common ad placements without cropping. Kling 4.0 offers four: 16:9, 9:16, 1:1 and 21:9.

A faster tier

Seedance 2.5 Turbo covers 720p and 1080p for iteration. Kling 4.0 has no separate fast variant on WaveSpeedAI.

Where the specs favor Kling 4.0

Reference videos and audio

Kling 4.0 reference-to-video takes up to 10 reference images, up to 5 reference videos and up to 3 reference audios (audios 5 to 30 seconds each). You point to them in the prompt as @Image1, @Video1 and @Audio1 in the order given, and keep_original_sound keeps a reference video’s own sound instead of generating new audio. For briefs built from existing footage and sound, this is a lot of control in one request.

First frame, last frame and keyframes

Kling 4.0 image-to-video starts from a first frame, can move toward an optional last frame, and accepts in-between keyframes in order, up to 10 images in total. That suits storyboard-style clips where you already know how the shot starts and ends.

Editing a clip you already have

Kling 4.0 video-edit takes a 3 to 30 second video and a prompt describing the change, keeping the scene, subject and motion. The original sound is kept by default, and up to 10 reference images can guide the edit. In our test, a 5-second coastal-road clip of a red vintage convertible was edited with a prompt to make it a snowy winter evening while keeping the car and its motion. The result kept the same car, driver and motion with snow on the road and cliffs, at 1280x720 with the audio kept. That is a single example, not a benchmark.

Extending a clip

Kling 4.0 video-extend generates a new segment of 3 to 30 seconds continuing from the last frame and returns the original and the new segment joined; only the new segment is generated and charged. You can also give a target last frame to move toward. In our test, a 5-second sailboat-at-sunrise clip was continued by 5 seconds: the boat and bay carried on and the camera rose to reveal a harbor, producing a 10-second clip with audio.

Where Seedance 2.5 offers the same workflows

Seedance 2.5 also has dedicated video-edit and video-extend endpoints. At up to 30 seconds per generation, Seedance 2.5 text-to-video also covers a full product demo or a short-drama beat in one continuous shot. Long takes up to 30 seconds are therefore available from either model, and teams that revise approved clips can keep the loop inside whichever family they prefer. Compared with Kling 3.0, where anything past 15 seconds means stitching clips, both newer models remove that constraint.

Where the previous Kling generation still fits

Kling 3.0 takes up to six shots in a single request through multi_prompt, and you can let the model split shots or define them yourself. Kling O3 with Kling Elements lets you register a character once and reuse it across clips, and both have native 4K tiers. If a brief depends on one of those features, Kling 3.0 and O3 are still the right Kling models to reach for.

A fair test: Kling 4.0 vs Seedance 2.5

Use the same briefs and assets. Same prompt, same reference images, same aspect ratio, and the same target duration where both models allow it.
Split the set by job type. For example: 5 product clips, 5 dialogue scenes, 5 clips built from reference video or audio, and 5 clips that edit or extend existing footage.
Score production criteria. Identity drift across shots, product shape and label accuracy, lip sync, camera adherence, and the number of generations needed for an approved clip.
Measure cost per approved clip. A model that costs more per generation but needs fewer retries can be cheaper in practice.
Route by job type. The likely outcome is not a single winner but a split, for example Seedance for 4K deliverables and large reference sets, Kling for reference-video briefs and frame-controlled clips.

The WaveSpeedAI Video Generator runs Kling 4.0 in four modes (Generate, Reference, Edit and Extend) and also runs Seedance 2.5, which is the quickest way to do a first pass before scripting the full test through the API. The Kling 4.0 collection lists all five models.

One integration for both

Both models use the same WaveSpeedAI request flow: submit to the model path, get a prediction ID, poll for the result. Switching is a matter of changing the path and a few model-specific parameters:

JOBS = {
    "long_take_4k": "bytedance/seedance-2.5/text-to-video",
    "reference_video": "kwaivgi/kling-v4.0/reference-to-video",
    "frame_controlled": "kwaivgi/kling-v4.0/image-to-video",
    "edit_existing": "kwaivgi/kling-v4.0/video-edit",
    "extend_existing": "kwaivgi/kling-v4.0/video-extend",
    "multi_shot": "kwaivgi/kling-v3.0-pro/text-to-video",
    "character_series": "kwaivgi/kling-video-o3-pro/reference-to-video",
}

With Kling 4.0 you POST to https://api.wavespeed.ai/api/v3/<model id>, receive a prediction ID, and poll https://api.wavespeed.ai/api/v3/predictions/<id>/result.

Pricing

Both families are billed per use with no subscription. The price basis differs, so compare it per approved clip rather than per second.

At the time of writing, Kling 4.0 text-to-video, image-to-video and video-extend cost $0.157 per second at 720p and $0.235 per second at 1080p, so a 5-second 720p clip is $0.785 and a 10-second 1080p clip is $2.35. Reference-to-video without a reference video uses the same rates. With reference videos, and for video-edit, billing uses counted seconds (output length plus the longer of the output length and the total reference-video length, each capped at 30 seconds) at $0.094 per counted second at 720p and $0.141 at 1080p; reference audios are not charged. Seedance 2.5 rates are set by resolution or tier and by whether audio is enabled.

Always check the Kling 4.0 API page and the Seedance 2.5 API page for current rates.

Bottom line

Neither model is a blanket winner, and we do not rank their output quality. Seedance 2.5 is the stronger fit when you need 4K, up to 30 reference images, or six aspect ratios. Kling 4.0 is the stronger fit when you want reference videos and audio, first-to-last-frame control, or clips of 3 to 30 seconds at 720p and 1080p with straightforward per-second pricing. Both cover long takes, native audio, editing and extension. Prepare a job-type test set and let your own results decide.

For the full list of Kling 4.0 endpoints and prices, see Kling 4.0 Is Live on WaveSpeedAI, and for the step from the previous Kling generation, see Kling 4.0 vs Kling 3.0.

FAQ

Is Kling 4.0 better than Seedance 2.5?

We have not benchmarked them head to head, so we do not rank them. The specs differ in ways that matter for planning: both generate clips of up to 30 seconds with native audio and have edit and extend endpoints, but Seedance 2.5 offers up to 4K output and up to 30 reference images, while Kling 4.0 offers 720p and 1080p, up to 10 reference images, 5 reference videos and 3 reference audios, and a first-frame, last-frame and keyframe image-to-video mode. Run both on your own briefs and compare cost per approved clip.

Which model should I use for commercial video?

Choose by the job. Seedance 2.5 fits briefs that need 4K output, many reference images, or six aspect ratios including 4:3 and 3:4. Kling 4.0 fits briefs built around reference videos and reference audio, first-to-last-frame control, or clips of 3 to 30 seconds with simple per-second pricing at 720p and 1080p. Kling 3.0 and O3 remain options for multi-shot prompts and Kling Elements.

How long can Kling 4.0 and Seedance 2.5 clips be?

Both reach 30 seconds per generation on WaveSpeedAI. Kling 4.0 accepts whole-second durations from 3 to 30 seconds on all five of its endpoints, with 5 seconds as the default. Seedance 2.5 text-to-video covers 4 to 30 seconds.

Does Kling 4.0 support video editing and extension?

Yes. Kling 4.0 has a video-edit endpoint, which changes a 3 to 30 second clip according to a prompt while keeping the scene, subject and motion, and a video-extend endpoint, which generates a new 3 to 30 second segment from the last frame and returns the original and the new segment joined. Seedance 2.5 has its own video-edit and video-extend endpoints.

Does Kling 4.0 generate 4K video?

Not on WaveSpeedAI. Kling 4.0 offers 720p (default) and 1080p there. Seedance 2.5 and the Kling 3.0 and O3 family have 4K tiers.

How is Kling 4.0 priced compared with Seedance 2.5?

Both are billed per use with no subscription. At the time of writing, Kling 4.0 text-to-video, image-to-video and video-extend cost $0.157 per second at 720p and $0.235 per second at 1080p. Reference-to-video with reference videos and video-edit use a counted-second rule. Seedance 2.5 rates depend on resolution and audio. Check the model pages for current prices.

Can I switch between Kling and Seedance without rewriting my integration?

Yes. On WaveSpeedAI both use the same submit-and-poll API pattern. The model path and a few model-specific parameters change; the request flow does not.