Web Messaging Guest API: File upload 413 on 4.8MB PNG despite 10MB config

NICE CXone API & Integrations
1

Stuck on the file upload flow for the Web Messaging Guest API. The org settings show a 10MB limit for file attachments, but the SDK client throws a 413 Payload Too Large when sending a 4.8MB PNG. Smaller files (under 2MB) work fine.

Here’s the upload sequence:

  1. Get the upload URL via the guest file upload endpoint with the file metadata.
  2. Receive the uploadUrl and uploadToken.
  3. Perform PUT to the uploadUrl with the file body.

The PUT request fails with 413. Checked the headers; Content-Length matches the file size. No custom middleware blocking it.

  • Genesys Cloud Web Messaging SDK v1.12.0
  • Node.js 18 runtime for the backend proxy
  • File: 4.8MB PNG, image/png
  • Org Limit: 10MB

Is there a hidden header requirement or a specific timeout on the upload URL that causes this? The docs are silent on pre-signed URL constraints.