Create AI avatar videos with full control over avatars, voices, scripts, and backgrounds using POST /v3/videos. Two creation modes via discriminated union on type:

• "type": "avatar" + avatar_id — use a HeyGen avatar from the library
• "type": "image" + image (AssetInput) — animate any photo via Avatar IV

Authentication

All requests require the X-Api-Key header. Set the HEYGEN_API_KEY environment variable.

curl -X GET "https://api.heygen.com/v3/avatars" \
  -H "X-Api-Key: $HEYGEN_API_KEY"

Tool Selection

If HeyGen MCP tools are available (mcp__heygen__*), prefer them over direct HTTP API calls — they handle authentication and request formatting automatically.

Task	MCP Tool	Fallback (Direct API)
Check video status / get URL	mcp__heygen__get_video	GET /v3/videos/{video_id}
List account videos	mcp__heygen__list_videos	GET /v3/videos
Delete a video	mcp__heygen__delete_video	DELETE /v3/videos/{video_id}

Video generation (POST /v3/videos) and avatar/voice listing are done via direct API calls — see reference files below.

Default Workflow

• List avatar looks — GET /v3/avatars/looks → pick a look, note its id (this is the avatar_id) and default_voice_id. See avatars.md
• List voices (if needed) — GET /v3/voices → pick a voice matching the avatar's gender/language. See voices.md
• Write the script — Structure scenes with one concept each. See scripts.md
• Generate the video — POST /v3/videos with avatar_id, voice_id, script, and optional background per scene. See video-generation.md
• Poll for completion — GET /v3/videos/{video_id} until status is completed. See video-status.md

Routing: This Skill vs Create Video

This skill = precise control (specific avatar, exact script, custom background). create-video = prompt-based ("make me a video about X", AI handles the rest).

Reference Files

Read these as needed — they contain endpoint details, request/response schemas, and code examples (curl, TypeScript, Python).

Core workflow:

• references/video-generation.md — POST /v3/videos request fields, avatar input modes, voice settings, backgrounds
• references/avatars.md — GET /v3/avatars (groups) and GET /v3/avatars/looks (looks → avatar_id)
• references/voices.md — GET /v3/voices with filtering by language, gender, engine
• references/video-status.md — GET /v3/videos/{id} polling patterns and download

Customization:

• references/scripts.md — Script writing, SSML break tags, pacing
• references/backgrounds.md — Solid color and image backgrounds
• references/captions.md — Auto-generated captions/subtitles
• references/text-overlays.md — Text overlays with fonts and positioning

Advanced:

• references/photo-avatars.md — Animate photos via type: "image" (Avatar IV), AI-generated avatars
• references/templates.md — Template listing and variable replacement
• references/remotion-integration.md — Using HeyGen avatars in Remotion compositions
• references/webhooks.md — Webhook endpoints and events
• references/assets.md — Uploading images, videos, audio
• references/dimensions.md — Resolution and aspect ratios
• references/quota.md — Credit system and usage limits

Best Practices

• Preview avatars before generating — Use GET /v3/avatars/looks and download preview_image_url so the user can see the avatar before committing
• Use avatar's default voice — Most avatars have a default_voice_id pre-matched for natural results
• Fallback: match gender manually — If no default voice, ensure avatar and voice genders match
• Use test mode for development — Set test: true to avoid consuming credits (output will be watermarked)
• Set generous timeouts — Video generation often takes 5-15 minutes, sometimes longer
• Validate inputs — Check avatar and voice IDs exist before generating

curl -X GET "https://api.heygen.com/v3/avatars" \
  -H "X-Api-Key: $HEYGEN_API_KEY"