Runway API Seedance 2.5 vs Sume: 4 to 30 s, 480p to 1080p

Runway's API changelog lists Seedance 2.5 (seedance2_5) as 4 to 30 second video at 480p or 720p, released 2026-08-07, and a later entry on 2026-08-15 adds 1080p for text-to-video, image-to-video and video-to-video. Sume's seedance-2.5 row has the same 4 to 30 second range and the same three resolutions. So 1080p is not what separates them; reference limits, billing and the request shape are.

Check the date of any Runway page you read: the first changelog entry names only 480p and 720p, and the 1080p entry came a week later.

What each page says

Both products serve the same model family under different ids.

Draft mode in Runway Agent

Runway's changelog also lists Seedance 2.5 Draft Mode in Agent on 2026-10-02, described as fast 480p drafts with post-generation enhancement. That is a feature of Runway's Agent product. Sume has no draft mode flag; the equivalent habit is to request resolution: "480p" and later re-submit at a higher resolution. The second request is a new generation, because Sume's video rows take no seed.

• Draft: seedance-2.5 at 480p.
• Final: the same prompt at 720p or 1080p.
• Expect a different take; do not promise a pixel match.

A 480p draft request

Using the Video Router with an explicit id and a vertical frame.

curl -X POST https://api.sume.com/v1/video-router/generate \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: seedance25-draft-001" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "A vertical UGC-style clip: a woman unboxes a skincare set at a bright desk",
    "resolution": "480p",
    "duration": 12,
    "aspect_ratio": "9:16",
    "mode": "async"
  }'

Sources

Runway's entries are on its API changelog and product changelog. Sume's range is stated on the Video Router page, and the request is documented in Video generation.