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Video Google · 2025-10

Veo 3.1 Fast API

Google Veo 3.1 Fast: 8-second clips at up to 4K from text or 3 images

720p$0.354per video
1080p$0.354per video
4K$1.62per video

Failed generations are not charged. Prices exclude taxes. Billed from your prepaid USD balance.

Exact cost for your settings →

Veo 3.1 Fast is the faster tier of Google's Veo 3.1, released in October 2025. On Jantaris it produces fixed 8-second clips in 16:9 or 9:16 at 720p, 1080p or 4K. Besides text-to-video it accepts up to 3 images in image_urls. Prompts can be up to 4,000 characters. Google also offers 4 and 6 second clips, explicit first and last frame fields, an audio switch and clip extension, but Jantaris does not expose those options yet.

Best for

  • Social ads and teasers in 9:16 or 16:9
  • Product shots guided by reference images
  • 4K B-roll for edits
  • Fast iteration on Veo prompts before a quality render

Prompting tips

  • Structure prompts like a shot description: subject, action, camera move, lens, lighting, sound.
  • Put spoken lines in quotes and describe ambient sound separately.
  • With images attached, say in the prompt what each one contributes: subject, outfit or setting.
  • Draft on Fast, then re-render the best prompt on Veo 3.1 (Quality).

FAQ

How much does the Veo 3.1 Fast API cost?

Veo 3.1 Fast is priced at from $0.354 per video. You see estimated_cost before the job runs, and failed generations are not charged.

How long are Veo 3.1 Fast videos?

Every clip on Jantaris is 8 seconds. For longer videos, generate several shots and join them in your editor.

Does Veo 3.1 Fast support 4K?

Yes. 720p, 1080p and 4K are available in both 16:9 and 9:16.

How to call Veo 3.1 Fast via API

curl https://jantaris.com/v1/generate?wait=60 \
  -H "Authorization: Bearer $JANTARIS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "veo-3.1-fast",
  "input": {
    "prompt": "A slow dolly shot through a neon-lit night market in the rain, reflections on wet asphalt, cinematic",
    "aspect_ratio": "16:9",
    "resolution": "720p"
  }
}'

Parameters

ParameterTypeAllowedDefault
prompt *string≤ 4000 chars
aspect_ratiostring16:9 9:1616:9
resolutionstring720p 1080p 4k720p
durationinteger88
image_urlsarraymax 3

The same schema is available from GET /v1/models/veo-3.1-fast.