Create Lipsync
Replaces the audio on an existing video and re-animates the speaker’s lip movements to match the new audio. Use mode: ‘speed’ for fast output or ‘precision’ for high-quality lip-sync.
Authorizations
HeyGen API key. Obtain from your HeyGen dashboard.
Headers
Optional client-supplied key for safely retrying mutations. Subsequent calls within 24 hours that share this key replay the original response — even if the request body differs slightly (a warning is logged). A retry that arrives while the original is still in flight gets a 409 request_in_progress. Keys must be 1–255 characters from [A-Za-z0-9_:.-]; a UUID is a safe default. Scope is per-endpoint and per-resource: the same key on a different route or path parameter is independent.
1 - 255^[A-Za-z0-9_\-:.]{1,255}$Body
Request body for POST /v3/lipsyncs.
Asset input via publicly accessible HTTPS URL.
- AssetUrl
- AssetId
Asset input via publicly accessible HTTPS URL.
- AssetUrl
- AssetId
Title for the lipsync job
Quality mode: 'speed' (faster) or 'precision' (higher quality, uses avatar inference)
speed, precision Webhook URL for completion notifications
ID included in webhook payload
Deprecated and ignored: captions are always generated; whether to display them is a download-side choice.
Preserve the source video's encoding specs (resolution, bitrate).
Allow dynamic duration adjustment
Remove background music
Enhance speech quality
Add watermark to output
Start time in seconds for partial lipsync
End time in seconds for partial lipsync
Frame rate mode: 'vfr', 'cfr', or 'passthrough'.
Destination folder ID in the caller's workspace, for example one returned by POST /v3/folders. Omit, pass null, or pass an empty string to place the result at the workspace root. The id must name a folder that is not in the trash and that the caller can write to. Assets library folders are accepted, but the HeyGen app files only assets in them, so a result placed there may not appear in the Assets library view. An unknown id, a folder in another workspace, a project of another kind such as a brand kit, or a trashed folder is rejected with 404 before anything is created.
Response
Successful response
Response for POST /v3/lipsyncs.

