Does Kling 3.0 do 9:16? Its guide is silent; Sume lists 3 ratios

You ask whether Kling 3.0 makes vertical video for Shorts and Reels. Kling's own VIDEO 3.0 guide gives a duration of 3 to 15 seconds, 1080p and 720p, and native audio in five languages, but it does not state aspect ratios or mention 9:16 (read 2026-10-04). A vendor page that is silent is not a no, and it is not a yes either.

The answer you can act on is the catalog of the API you call. For Sume, the kling-3 row lists 16:9, 9:16 and 1:1, with resolutions 720p and 1080p and durations 4 to 15 seconds. It does not list 4:3, 3:4 or 21:9.

Read it yourself

The video generation docs describe GET /v1/videos/models, which returns supported_aspect_ratios per model. This script prints the three fields that matter for a vertical Short.

import os
import requests

resp = requests.get(
    "https://api.sume.com/v1/videos/models",
    headers={"Authorization": f"Bearer {os.environ['SUME_API_KEY']}"},
)
for model in resp.json()["data"]:
    if model["id"] == "kling-3":
        print(model["supported_aspect_ratios"])
        print(model["supported_resolutions"])
        print(model["supported_durations"])

What to do with it

For a Short, send aspect_ratio: "9:16" and resolution: "1080p" and the clip comes back vertical at the model's own framing, so you do not crop a 16:9 render. If you need 3:4 or 4:3, Kling is the wrong row on Sume; seedance-2 and wan-3.0 list both. YouTube counts a video as a Short when it is square or vertical and up to three minutes, so 9:16 and 1:1 from kling-3 both qualify.

Treat every vendor spec page as a claim about the vendor's own product and the Sume catalog as the claim about what you can call. When they differ, as the duration floor does at 3 versus 4 seconds, the catalog wins.