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Documentation Index

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Pricing: $0.034/second. Endpoint: POST /v1/models/heygen/v3/video-agent/runs.
Generate videos with a single prompt. Describe what you want in plain text, and the agent handles avatar selection, scripting, scene composition - all in one.

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Overview

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Pricing

  • Base price: $0.034/second
  • Note: Usage-based, per second of generated video

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HeyGen Video Agent V3 API

Endpoint: POST /v1/models/heygen/v3/video-agent/runs

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Run the model

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Python

import requests

response = requests.post(
    "https://api.runflow.io/v1/models/heygen/v3/video-agent/runs",
    headers={"Authorization": "Bearer RUNFLOW_API_KEY"},
    json={
        "input": {
            "prompt": "Create a 20-second professional product announcement video from a CTO introducing a new AI video platform to prospective customers. Modern office backdrop, warm professional lighting, confident tone, medium shot, minimal graphics. End with call-to-action."
        },
        "callback_url": "https://your-server.com/webhook"
    },
)

data = response.json()
print(data)

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Node.js

const response = await fetch(
  "https://api.runflow.io/v1/models/heygen/v3/video-agent/runs",
  {
    method: "POST",
    headers: {
      "Authorization": "Bearer RUNFLOW_API_KEY",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
        "input": {
            "prompt": "Create a 20-second professional product announcement video from a CTO introducing a new AI video platform to prospective customers. Modern office backdrop, warm professional lighting, confident tone, medium shot, minimal graphics. End with call-to-action."
        },
        "callback_url": "https://your-server.com/webhook"
    }),
  }
);

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

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cURL

curl -X POST https://api.runflow.io/v1/models/heygen/v3/video-agent/runs \
  -H "Authorization: Bearer $RUNFLOW_API_KEY" \
  -H "Content-Type: application/json" \
  --data-binary @- <<'JSON'
{
    "input": {
        "prompt": "Create a 20-second professional product announcement video from a CTO introducing a new AI video platform to prospective customers. Modern office backdrop, warm professional lighting, confident tone, medium shot, minimal graphics. End with call-to-action."
    },
    "callback_url": "https://your-server.com/webhook"
}
JSON

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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.

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Input schema

FieldTypeRequiredAllowed valuesDescription
promptstringrequiredAnyNatural language prompt describing the video to generate. The agent handles avatar selection, script, and production automatically.
orientationstringoptionallandscape, portraitVideo orientation. Auto-detected from the prompt if omitted.
avatarstringoptionalAnyAvatar to use in the video. Set to ‘auto’ to let the agent auto-select based on the prompt.
file_urlsfile_listoptionalAnyURLs of files to include as assets in the video (images, videos, audio, PDFs). Maximum 20 files.
incognito_modebooleanoptionalAnyWhen enabled, disables the agent’s memory functions.
style_idstringoptionalAnyStyle template ID from the /v3/video-agent/styles endpoint.
voicestringoptionalAnyVoice for narration. Set to ‘auto’ to let the agent auto-select.

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Output schema

FieldTypeDescription
outputsjsonUnified output array.
seedjsonSeed used for generation, or null.
timingjsonProvider timing info, or null.
nsfw_detectedjsonNSFW flag, or null.

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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.

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Additional Resources

Browse all models

Browse the catalog.

Run lifecycle

Callbacks, polling, statuses.

Callbacks

Handle async results.

Pricing

How requests bill out.