Documentation Index
Fetch the complete documentation index at: https://heygen-1fa696a7.mintlify.app/llms.txt
Use this file to discover all available pages before exploring further.
Video Generation — Avatar IV
| Avatar Type | Rate |
|---|
| Photo Avatar | 0.1 credits / sec |
| Digital Twin | 0.1 credits / sec |
| Studio Avatar | 0.1 credits / sec |
Video Generation — Avatar III
| Avatar Type | Rate |
|---|
| Photo Avatar | 0.0033 credits / sec |
| Digital Twin | 0.0033 credits / sec |
| Studio Avatar | 0.0033 credits / sec |
Video Agent
| Feature | Rate |
|---|
| Prompt to Video | 0.0667 credits / sec |
Video Translation
| Mode | Rate |
|---|
| Speed — Audio Only | 0.05 credits / sec |
| Speed — Lip Sync | 0.05 credits / sec |
| Precision — Lip Sync | 0.1 credits / sec |
| Proofread | 0.00833 credits / sec |
Lipsync
| Mode | Rate |
|---|
| Speed | 0.05 credits / sec |
| Precision | 0.1 credits / sec |
Text-to-Speech
| Model | Rate |
|---|
| Speech — Starfish | 0.000333 credits / sec |
Avatar Creation
| Operation | Rate |
|---|
| Digital Twin | 1 credit / call |
| Photo Avatar | 1 credit / call |
Concurrency Limits
| Plan | Max Concurrent Video Jobs |
|---|
| Enterprise | 20+ (varies by contract) |
429 Too Many Requests with a Retry-After header.
Endpoint Limits
Resources provided to POST /v3/videos must meet these limits. Invalid resources will cause render failures.
| Resource Type | Supported Formats | Max File Size | Max Resolution |
|---|
| Video | MP4, WebM | 100 MB | < 2K |
| Image | JPG, PNG | 50 MB | < 2K |
| Audio | WAV, MP3 | 50 MB | — |
- Resource URLs must be publicly accessible (no authentication required).
- The file extension must match the actual file format.
- Files must not be corrupted or malformed.
- Script text: Maximum 5,000 characters.
- Audio input: Maximum 10 minutes (600 seconds).
- Prompt: 1–10,000 characters.
- File attachments: Up to 20 files. Supported types: image (PNG, JPEG), video (MP4, WebM), audio (MP3, WAV), and PDF.
- Files can be provided as an
asset_id (from POST /v3/assets), an HTTPS URL, or base64-encoded content.
Asset Upload (POST /v3/assets)
- Maximum file size: 32 MB.
- Supported types: Image (PNG, JPEG), video (MP4, WebM), audio (MP3, WAV), and PDF.
Text-to-Speech Input (POST /v3/voices/speech)
- Text length: 1–5,000 characters.
- Speed multiplier: 0.5× to 2.0×.
- Input type: Plain text or SSML markup.
Output Video Specifications
- Frame rate: 25 fps for videos containing avatars.
- Resolution: Width and height must each be between 128 and 4,096 pixels. Default output is 1080p (up to 4K on Enterprise).
- Aspect ratio: 16:9 or 9:16.
- Maximum scenes: 50 per video.
- Maximum duration: Custom (contact your account team).
Most list endpoints use cursor-based pagination with a limit parameter and next_token for the next page.
| Endpoint | Default | Max |
|---|
GET /v3/videos | 10 | 100 |
GET /v3/avatars | 20 | 50 |
GET /v3/avatars/looks | 20 | 50 |
GET /v3/voices | 20 | 100 |
GET /v3/video-agents/styles | 20 | 100 |
GET /v3/video-translations | 10 | 100 |
GET /v3/webhooks/endpoints | 10 | 100 |
GET /v3/webhooks/events | 10 | 100 |
GET /v3/video-agents/sessions/{id}/resources | 8 | 100 |
Rate Limiting
All endpoints enforce rate limits. When exceeded, the API returns 429 Too Many Requests with a Retry-After header indicating the number of seconds to wait before retrying.
