HeyGen Assets folders (flat) vs Sume media inputs by HTTPS URL

HeyGen's Assets library folders can now be read with GET /v3/folders/{folder_id} and used in folder_id destinations, but they are created in the app and are flat. Sume has no folder concept in its launch requests: you pass media as public HTTPS URLs in the documented fields.

HeyGen facts are from its API changelog; Sume facts from Media inputs, read 2026-10-01.

What changed at HeyGen?

Existing Assets library folder ids are accepted by routes with a folder_id destination. POST /v3/folders cannot create them or nest a folder inside one. The app shows only assets in these folders, so a video or translation placed there may not appear in that view.

How does Sume take media in?

Launch generation requests accept media as public HTTPS URLs in the exact fields of the live OpenAPI schema. You do not need to create a separate Sume asset before submitting Avatar 1.0, Avatar Video, face-swap or caption requests.

Which URLs are rejected?

Localhost, private-network URLs, non-HTTPS URLs, signed or private URLs and mismatched content types are rejected before generation is submitted. A pre-signed link from another storage service will not work; host the file at a plain public URL.

Is there any import step?

For Timeline compose, yes: both URLs must already be this workspace's media.sume.com artifact or asset, so import first with POST /v1/media-imports, which requires an Idempotency-Key. That is an import, not a folder. For uploading from a local machine, see upload a local file over MCP.