July 22, 2025 | Uploadcare docs

Subdomains rollout

We have started implementing unique CDN subdomains for each project, replacing the generic https://ucarecdn.com/ domain. The default CNAME has been updated to use a subdomain in the format https://<HASH>.ucarecd.net/<UUID>/, where each project is assigned a unique subdomain (replacing the <HASH>).

Potential breaking change

If your application has hardcoded logic or Content Security Policy (CSP) settings tied to ucarecdn.com, you may experience issues with file uploads or thumbnail rendering.

We recommend locking that in the File Uploader configuration:

<uc-config
  cdn-cname="https://ucarecdn.com/"
  ...
</uc-config>

An example for jQuery Uploader configuration:

<input type="hidden" role="uploadcare-uploader"
  data-public-key="YOUR_PUBLIC_KEY"
  data-cdn-base="https://ucarecdn.com/"
/>

Introducing subdomains will enable enhanced access control, facilitate signed URLs without requiring a custom CNAME, enforce usage restrictions, and help prevent abuse. Existing customers will keep access to the legacy CDN domain type https://ucarecdn.com/, together with new ones. New customers will only have access to new subdomain names.