Notion file upload: 20 MB direct limit, 1-hour attach window, Sume

Notion's direct file upload handles files up to 20 MB, and an upload that is not attached within one hour is archived (Notion docs, read 2026-10-02). To put a Sume image on a page, upload it, then attach it in the same handler run; for a larger video, use Notion's multi-part upload described on the same page.

What the page says

The changelog (September 22, 2026) separately says the File Upload API now accepts CAD and 3D formats such as .step, .stl, .obj and .glb. That is a Notion acceptance change, not something Sume produces.

Where Sume fits

A Sume job webhook for a finished image carries payload.artifacts[] with a url and content_type (webhook docs). Fetch that URL in your handler, send the bytes to Notion, then attach the upload to the page. The one-hour window is generous for that sequence, but not for a design where you create the Notion upload at submit time and wait for the render.

Order of operations

• Submit the Sume job with a webhook_url; store the job_id against the Notion page id.
• On the signed job.completed event, create the Notion file upload, send the file, and attach it right away.
• If your handler fails after creating the upload, create a new one on retry rather than reusing the old id, and key the page update on job_id so retries do not attach the file twice.
• Return 2xx to Sume only after the event is stored; the write-back itself can run behind it.

Honest limit

Notion's page does not describe an external-URL mode for these uploads, so pasting a Sume URL as an upload source is not documented there. Sume does not push files to Notion; the handler is yours. Check the file size against 20 MB before choosing direct or multi-part.