2026-09-29

How long does a Seedance 2.5 video take, and how do you wait for it?

Sume's docs say video generation takes 30 seconds to several minutes. Poll GET /v1/videos/{id} every 30 seconds or pass callback_url for a signed webhook.

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Sume's video docs put generation at 30 seconds to several minutes, depending on the model and parameters, and they publish no per-model timing for seedance-2.5. Poll GET /v1/videos/{id} about every 30 seconds, or pass an HTTPS callback_url and Sume POSTs a signed webhook when the job finishes.

How should I wait for a long clip?

Pick by how your service runs. A worker that stays alive can poll; a serverless function should take the webhook.

Waiting options for POST /v1/videos, read 2026-09-29.
Option	How	Use when
Poll	`GET /v1/videos/{id}` about every 30 s until `completed`	A process can stay alive
Webhook	`callback_url` (HTTPS) on the request	Serverless or queue-driven apps
Both	Webhook first, one poll as a safety net	You cannot lose a result

How do I request the webhook?

Add callback_url and an Idempotency-Key, so a retried submit does not queue a second job.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: seedance-25-hook-001" \
  -d '{
    "model": "seedance-2.5",
    "prompt": "Time-lapse of clouds over a mountain lake",
    "duration": 30,
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "callback_url": "https://example.com/hooks/video"
  }'

How do I verify the webhook?

Sume signs the raw JSON body and sends x-sume-webhook-timestamp and x-sume-webhook-signature. Verify both against your secret before you trust the payload, and refuse to run with an empty secret.

Does a longer clip take proportionally longer?

The docs do not say, so measure your own p50 and p95 for the lengths and resolutions you use before you set a timeout. See AI video API timeouts.

Sources

Video generation