Wan 3.0 vertical video: 9:16 for Reels, Shorts and TikTok

Yes, Wan 3.0 makes vertical video. Send aspect_ratio: "9:16" to wan-3.0 on POST /v1/videos, with a duration of 2 to 30 seconds and a resolution of 480p, 720p or 1080p. The other ratios it lists are 16:9, 4:3, 1:1 and 3:4.

Both fal's Wan 3 page and Alibaba Cloud's guide list those five ratios, read 2026-09-29; Alibaba also lists an adaptive default. Sume's fields are from Video generation.

What is the request?

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: wan-vertical-001" \
  -d '{
    "model": "wan-3.0",
    "prompt": "A barista pours latte art, close overhead shot, warm morning light",
    "duration": 6,
    "resolution": "720p",
    "aspect_ratio": "9:16"
  }'

Which ratios does Wan 3.0 accept?

Do I need to say 9:16 in the prompt too?

Set the field; that is what the model reads for shape. In the prompt, describe framing that suits a tall frame: a subject centred, action along the vertical axis, space at the top for captions.

How long can a Short or Reel clip be?

Wan 3.0 goes to 30 seconds. Each platform sets its own limits on what it accepts; check the platform's own help page before you publish rather than relying on a number from a blog.