Choosing a Video Generation API in 2026 - Seedance, Kling, Veo, Wan

Asking which video API is best is like asking which lens is best: it depends on the shot. My short version: Seedance 2.5 when you need one long take of up to 30 seconds with sound, Kling 3.0 for multi-shot scenes up to 15 seconds and 4K, Veo 3.1 (Quality) for polished 8-second clips up to 4K with sound always on, and Wan 3.0 when you want long 4K footage in a single run or the cheapest low-resolution drafts. On Kadraris all four are called through the same AI video generator API using a single key and balance. Veo is charged per 8-second clip, the other three per second.

I call these models from my own projects. Below is what separates them from a developer's point of view, followed by a script to test them against each other on your prompts.

Pick by job

Use this as a starting point. Results vary a lot by subject, so your own prompts are the only test that counts.

Specs side by side

Numbers below were checked in October 2026 against our schemas and the makers' docs. Features available only directly from a maker are flagged in the sections that follow.

Release dates: Seedance 2.5 on July 31, 2026; Kling 3.0 in February 2026, global from March; Veo 3.1 in 2025 with 2026 updates; Wan 3.0 on August 6, 2026 as a public beta. Resolution steps: Seedance 480p, 720p, 1080p; Kling 720p, 1080p, 4K; Veo 720p, 1080p, 4K; Wan 480P, 720P, 1080P, 2K, 4K.

Each model's allowed values are in the input_schema returned by GET /v1/models/{id}. Watch the casing: Wan expects 720P, the other three 720p.

Seedance 2.5 for long uninterrupted takes

When a scene needs room, I go to Seedance 2.5. Up to thirty seconds in a single generation gives you one shot with stable light and characters and no cuts to disguise.

Strengths:

• 4 to 30 seconds per run, with an option to extend further.
• Sound rendered in the same pass.
• Generous references: ByteDance quotes 30 pictures, 10 clips and 10 sound files in one call.
• It can start from a supplied first frame.

Weak spot: the ceiling is 1080p on Kadraris. That is fine for vertical video on phones, thin for a 4K brand piece.

Full parameters with Python examples: Seedance 2.5 API guide.

Kling 3.0 for short scenes with cuts and dialogue

Kuaishou announced Kling 3.0 at the start of February 2026 and launched it worldwide in March. It is designed for short narrative pieces.

Strengths:

• Up to 15 seconds per run.
• Write a sequence of shots in a single prompt and Kling edits between them during generation, keeping the cast consistent. The vendor's dedicated multi-shot mode, with separate prompts and lengths per shot, is not on Kadraris yet.
• Optional native sound (generate_audio) with lip sync per character and several speakers in one scene.
• 720p, 1080p or 4K.

Weak spot: one take cannot pass 15 seconds, and multi-shot prompts take more effort to write. If all you need is one tidy shot, Veo or Seedance with a short prompt usually gets there faster.

My rule: briefs like "two people talking in a short scene" go to Kling; briefs like "a gorgeous shot of X" usually do not.

Veo 3.1 for short, high-resolution clips

Here, Veo 3.1 has one length, eight seconds, in 720p, 1080p or 4K, and the price is per clip (4K costs more). Dialogue, ambience and effects are always generated and included; there is no off switch.

Strengths:

• Lighting and materials look outstanding, and the main model reaches 4K.
• Three reference images can keep a subject consistent.
• Simple pricing: one clip, one rate.

Google's direct API also offers shorter 4 s and 6 s clips, start and end frames, and extending a clip by 7 s at a time. Kadraris does not expose those options yet.

Weak spot: eight seconds goes fast, and you get just 16:9 or 9:16. Every run is billed as a full 8-second clip, and at entry tiers its per-second cost is the highest of the four (only Seedance 2.5 at 720p and 1080p costs more per second), so I keep it for final renders, not exploration.

Wan 3.0 for long clips up to 4K

Alibaba released Wan 3.0 on August 6, 2026, replacing Wan 2.7. It runs on the same Kadraris key, alongside the more capable Wan 3.0 Video Prime; the previous model, Wan 2.7 Video, does up to 15 s at 1080P.

Strengths:

• 2 to 30 seconds in one continuous run.
• Five resolution steps from 480P to 4K, each with its own rate, which makes low-res drafts cheap.
• Audio comes with the clip unless you turn it off.
• References: ten pictures, five clips, five sound files.
• Input can be a presentation, a spreadsheet, a PDF or a public URL, which it turns into a video.

Note that Wan 3.0 weights are not public. If you must run video generation on your own hardware, Wan 2.2 under Apache 2.0 is the newest Wan you can download, at a quality cost.

Direct comparisons:

• against Seedance 2.5
• against Kling 3.0
• against its Prime version

A/B test script for all four

Because every model sits behind the same endpoint, a comparison is just iteration. The script below submits one prompt four times, collects the results and prints what each cost.

import os, time, requests

API = "https://kadraris.com/v1"
KEY = os.environ["KADRARIS_API_KEY"]
HEADERS = {"Authorization": f"Bearer {KEY}"}

PROMPT = (
    "A barista pours latte art in a sunlit cafe, close-up, "
    "shallow depth of field, soft clinking of cups and quiet chatter"
)

# per-model extras; Wan wants uppercase resolution values
JOBS = {
    "seedance-2.5": {"duration": 8, "resolution": "720p"},
    "kling-3.0": {"duration": 8},
    "veo-3.1": {"duration": 8, "resolution": "720p"},
    "wan-3.0": {"duration": 8, "resolution": "720P"},
}

started = {}
for model, extra in JOBS.items():
    inp = {"prompt": PROMPT, "aspect_ratio": "16:9", **extra}
    r = requests.post(f"{API}/generate", headers=HEADERS,
                      json={"model": model, "input": inp}, timeout=30)
    data = r.json()
    if r.status_code != 202:
        print(model, "refused:", data["error"]["message"])
        continue
    started[model] = data["id"]
    print(model, "queued, estimate", data["estimated_cost"])

waiting = dict(started)
while waiting:
    time.sleep(10)
    for model, tid in list(waiting.items()):
        t = requests.get(f"{API}/tasks/{tid}",
                         headers=HEADERS, timeout=30).json()
        if t["status"] == "succeeded":
            url = t["output"][0]["url"]
            with open(f"{model}.mp4", "wb") as f:
                f.write(requests.get(url, timeout=120).content)
            print(model, "saved, cost", t["cost"])
            del waiting[model]
        elif t["status"] == "failed":
            print(model, "failed, no charge:", t["error"])
            del waiting[model]

What the script takes care of:

• Per-model parameters. Resolution values vary between models (Wan uses capitals), so Kling gets no resolution and falls back to its default. Look up each schema with GET /v1/models/{id} before adding fields.
• Validation before billing. A bad input returns 422 with an explanation and costs nothing.
• Free failures. If a vendor filter blocks the prompt on one model, that task ends as failed with zero cost.

For bigger batches, let the server call you instead of polling; the setup is in async AI video with webhooks.

What the four cost

Billing units differ (seconds for three, whole clips for Veo), and every model charges more at higher resolution. So duration and resolution move the total as much as the model does.

Starting rates at the lowest resolution:

• Seedance 2.5: from $0.261 per second
• Kling 3.0: from $0.0963 per second
• Veo 3.1 (Quality): from $2.53 per video
• Wan 3.0: from $0.0777 per second

The test script costs at least 8 × from $0.261 per second + 8 × from $0.0963 per second + 1 × from $2.53 per video + 8 × from $0.0777 per second; at 720p and up the real total is higher. You see estimated_cost for your settings in the response before any work starts, and the AI cost calculator adds up a batch for you. Worked budgets, such as a 30-second reel, are in AI video cost per second.

How I use them on client work

1. Sketch ideas cheaply: four 480P variants per prompt on Wan 3.0.
2. Settle the visual style by making a start image first (Python image generation guide).
3. Render for real on the model that matches the deliverable, using the job table at the top.
4. Save files immediately; result URLs do not last.

No code? The same models are available in Studio, paid from the same balance.

Questions

Which of the four is best for a beginner's first API test?

Seedance 2.5 at 480p. It is forgiving with simple prompts and accepts lengths from 4 to 30 seconds, so you can see quickly how duration affects cost. If the lowest rate matters most, Wan 3.0 at 480P costs less per second.

Why does my Wan request return 422?

The most common cause is lowercase resolution. Wan expects 480P, 720P and so on, while the other three use lowercase. GET /v1/models/wan-3.0 shows the exact allowed values.

Can I get first and last frame control on Veo 3.1 here?

Not on Kadraris at the moment. Veo 3.1 runs only as a fixed 8-second clip here; frame control, 4- and 6-second lengths and extensions are limited to Google's own API.

Do I need four accounts for this comparison?

No. One Kadraris key and one balance cover all four; you only change the model field in POST /v1/generate.