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Pricing: $0.1/second. Endpoint: POST /v1/models/google/veo3.1/fast/image-to-video/runs.
Generate videos from your image prompts using Veo 3.1 fast.

Overview

Pricing

  • Base price: $0.1/second
  • Note: Without audio

Veo 3.1 Fast - Image to Video API

Endpoint: POST /v1/models/google/veo3.1/fast/image-to-video/runs

Run the model

Python

import requests

response = requests.post(
    "https://api.runflow.io/v1/models/google/veo3.1/fast/image-to-video/runs",
    headers={"Authorization": "Bearer RUNFLOW_API_KEY"},
    json={
        "input": {
            "prompt": "The woman walks slowly down the cathedral aisle, her footsteps echoing softly against the marble floor. Shafts of rainbow light from the rose window sweep across her path as clouds move outside. She pauses to look up at the vaulted ceiling, dust motes dancing in the colored beams. Ambient cathedral reverb, distant organ notes.",
            "image_url": "https://public.runflow.io/images/models/black-forest-labs/flux-2-max/example-output-0.webp"
        },
        "callback_url": "https://your-server.com/webhook"
    },
)

data = response.json()
print(data)

Node.js

const response = await fetch(
  "https://api.runflow.io/v1/models/google/veo3.1/fast/image-to-video/runs",
  {
    method: "POST",
    headers: {
      "Authorization": "Bearer RUNFLOW_API_KEY",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
        "input": {
            "prompt": "The woman walks slowly down the cathedral aisle, her footsteps echoing softly against the marble floor. Shafts of rainbow light from the rose window sweep across her path as clouds move outside. She pauses to look up at the vaulted ceiling, dust motes dancing in the colored beams. Ambient cathedral reverb, distant organ notes.",
            "image_url": "https://public.runflow.io/images/models/black-forest-labs/flux-2-max/example-output-0.webp"
        },
        "callback_url": "https://your-server.com/webhook"
    }),
  }
);

const data = await response.json();
console.log(data);

cURL

curl -X POST https://api.runflow.io/v1/models/google/veo3.1/fast/image-to-video/runs \
  -H "Authorization: Bearer $RUNFLOW_API_KEY" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'JSON'
{
    "input": {
        "prompt": "The woman walks slowly down the cathedral aisle, her footsteps echoing softly against the marble floor. Shafts of rainbow light from the rose window sweep across her path as clouds move outside. She pauses to look up at the vaulted ceiling, dust motes dancing in the colored beams. Ambient cathedral reverb, distant organ notes.",
        "image_url": "https://public.runflow.io/images/models/black-forest-labs/flux-2-max/example-output-0.webp"
    },
    "callback_url": "https://your-server.com/webhook"
}
JSON

Request parameters

ParameterTypeRequiredDescription
inputobjectrequiredModel input parameters. See “Input schema” below.
callback_urlstring | nulloptionalWebhook URL - POSTed when the run reaches a terminal state.
metadataobject | nulloptionalArbitrary key-value pairs attached to the run.

Input schema

FieldTypeRequiredAllowed valuesDescription
promptstringrequiredAnyThe text prompt describing the video you want to generate
auto_fixbooleanoptionalAnyWhether to automatically attempt to fix prompts that fail content policy or other validation checks by rewriting them.
durationstringoptional4s, 6s, 8sThe duration of the generated video.
generate_audiobooleanoptionalAnyWhether to generate audio for the video.
resolutionstringoptional720p, 1080p, 4kThe resolution of the generated video.
aspect_ratiostringoptionalauto, 16:9, 9:16The aspect ratio of the generated video. Only 16:9 and 9:16 are supported.
image_urlimagerequiredAnyURL of the input image to animate. Should be 720p or higher resolution in 16:9 or 9:16 aspect ratio. If the image is not in 16:9 or 9:16 aspect ratio, it will be cropped to fit.
safety_tolerancestringoptional1, 2, 3, 4, 5, 6The safety tolerance level for content moderation. 1 is the most strict (blocks most content), 6 is the least strict.
seedintegeroptionalAnyThe seed for the random number generator.
negative_promptstringoptionalAnyA negative prompt to guide the video generation.

Output schema

FieldTypeDescription
outputsjsonUnified output array - one entry per generated artifact with url/type/width/height/duration/etc.
nsfw_detectedjsontrue if the provider flagged output as NSFW, false if cleared, null if not checked.
seedjsonDeterministic seed used for generation, or null if the provider doesn’t return one.
timingjsonProvider timing info (inference_ms etc.), or null.

Callback payload

When you provide a callback_url, Runflow POSTs to it once the run reaches a terminal state.
FieldTypeDescription
eventstringEvent type: “run.completed”, “run.failed”, or “run.cancelled”.
run_idstringThe unique identifier of the run.
statusstringTerminal status: “succeeded”, “failed”, or “cancelled”.
outputobject | nullThe run output. Null if the run failed or was cancelled.
duration_msnumber | nullTotal run duration in milliseconds.
created_atstring | nullISO 8601 timestamp when the run was created.
completed_atstring | nullISO 8601 timestamp when the run reached terminal state.
metadataobject | nullThe metadata object passed at run creation, if any.
  • Retries: 3 attempts with exponential backoff (1s, 2s). Retries on 5xx / network errors only.
  • Headers: Runflow-Request-Id is always sent. Runflow-Signature is sent if a signing secret is configured.

Additional Resources

Browse all models

Browse the catalog.

Run lifecycle

Callbacks, polling, statuses.

Callbacks

Handle async results.

Pricing

How requests bill out.