HeyGen modelsvideo generation api

heygen/heygen-avatar4/digital-twin

Name: HeyGen Avatar 4 Digital Twin
Author: HeyGen

Heygen Avatar4 Digital Twin is HeyGen's text-to-video AI model. Turn written scripts and prompts into professional-quality video clips with realistic motion, lighting, and scene composition.

Input

Aspect Ratio(string)

The aspect ratio of the generated image. Allowed values: 21:9, 16:9, 3:2, 4:3, 5:4, 1:1, 4:5, 3:4, 2:3, 9:16.

Audio Url(string)

URL of an audio file for the avatar to lip-sync to. When provided, the avatar uses this audio instead of text-to-speech.

Voice(string)

The voice ID to use for the avatar.

Avatar ID(string)

The character/avatar ID to use.

Idle

Example output — click Run to generate your own

Production endpoint

Send your first request

OpenAI-compatible endpoint with unified authentication and usage tracking.

POSThttps://api.sandbase.ai/v1/run

Model IDheygen/heygen-avatar4/digital-twin

Input Schema

4 parameters · 0 required · 4 optional

Parameter	Type	Required	Description
`audio`	string	Optional	URL of an audio file for the avatar to lip-sync to. When provided, the avatar uses this audio instead of text-to-speech.
`voice`	string	Optional	The voice ID to use for the avatar.
`avatar_id`	string	Optional	The character/avatar ID to use.
`aspect_ratio`	string	Optional	The aspect ratio of the generated image. · Options: 21:9, 16:9, 3:2, 4:3, 5:4, 1:1, 4:5, 3:4, 2:3, 9:16 21:916:93:24:35:41:14:53:42:39:16

Output Schema

Field	Type	Description
`id`	string	Unique identifier for the generation task
`status`	string	Task status: pending, running, completed, failed, timeout
`model`	string	Model used for the generation
`outputs`	array	Array of output items
`outputs[].url`	string	URL of the generated artifact
`outputs[].content_type`	string	MIME type (e.g. image/png, video/mp4)
`error`	object \| null	Error details if failed, null on success
`error.type`	string	Machine-readable error type code
`error.message`	string	Human-readable error description

Async Workflow

This model uses asynchronous execution. Submit a request and poll for the result.

Submit — POST to /v1/run, receive an id
Poll — GET /v1/run/{id} until status is completed, failed, or timeout
Retrieve — Read outputs from the completed response

Code Examples

Ready-to-run snippets

# Step 1: Submit
curl -X POST https://api.sandbase.ai/v1/run \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
  "model": "heygen/heygen-avatar4/digital-twin",
  "prompt": "a beautiful sunset over mountains"
}'

# Step 2: Poll result (replace <id>)
curl https://api.sandbase.ai/v1/run/<id> \
  -H "Authorization: Bearer YOUR_API_KEY"

← Back to HeyGen Avatar 4 Digital Twin

API README

HeyGen Avatar 4 Digital Twin

heygen/heygen-avatar4/digital-twin creates a talking digital-human video whose facial movement, timing, and expression follow supplied speech or creative direction. Avatar 4 Digital Twin emphasizes lifelike portrait motion, expressive gestures, and reliable identity across repeated presenter videos. This combination makes the model a practical choice when the creative outcome depends on those qualities rather than on a generic media conversion.

For production work with heygen/heygen-avatar4/digital-twin, the workflow suits explainers, training, localization, personalized outreach, and presenter-led content where a reusable human presence needs to deliver changing material. The result is most reliable when the source material and creative brief clearly describe the intended subject, progression, visual or sonic character, and the qualities that must remain unchanged.

Highlights

Speech-driven facial animation aligns mouth shapes, expression, and timing with the performance.

Avatar 4 expression produces lifelike facial movement and presenter gestures.

Presenter consistency supports repeated videos without reshooting the same person.

Expressive performance turns scripted material into an engaging on-camera delivery.

Pricing

Generated or processed duration	Price
Per second	$0.100

When to Use

✅ Good fit	❌ Consider alternatives
The model's named workflow matches the source material and intended output	A different input modality or model route is required
A managed asynchronous result is suitable for the production pipeline	A synchronous, interactive editor is essential
The documented controls cover the required duration, framing, or format	The project needs controls outside this endpoint's schema
Creative iteration benefits from a repeatable request structure	Exact deterministic pixels, frames, geometry, or samples are mandatory
A finished downloadable media asset is the desired deliverable	Editable source layers or a native project file are required

Prompt Guide

For audio transformation, state the intended result first, then add the subject or source treatment, progression, style, and delivery constraints. Keep one creative variable per phrase, use the documented field names for controls, and change one setting at a time when comparing results.

{
  "aspect_ratio": "21:9",
  "audio": "https://example.com/source.wav"
}

Technical Specs

Spec	Value
Model ID	`heygen/heygen-avatar4/digital-twin`
Inputs	aspect_ratio, audio, avatar_id, voice
Required inputs	None
Output fields	content_type, url
Execution	Async (submit, then poll for result)
Aspect Ratio	21:9 / 16:9 / 3:2 / 4:3 / 5:4 / 1:1 / 4:5 / 3:4 / 2:3 / 9:16