A file stops working after its URL is rewritten

First request the rewritten CDN URL directly and check its status, content type, redirects, and response headers. A provider may block the origin request, cache an error response, or return a different content type.

If a particular file must remain on the website origin, add a distinctive path or filename fragment to Ignore Files. Matching URLs are then left unchanged. Prefer a narrow fragment so unrelated files can still use the CDN.

How do I configure my CDN service?

Create an origin-pull distribution using the Joomla website as its origin. The provider should give you a hostname that can retrieve the same public file paths as the website. Provider consoles change independently of CDN for Joomla!, so follow the provider's current documentation for origin, HTTPS, cache, and purge settings.

Then follow Using CDN for Joomla! to enter the hostname and verify the rewritten URLs.

Fonts fail with a CORS error

The font response returned to the browser must include an appropriate Access-Control-Allow-Origin header. Configure that header on the origin or CDN service that actually serves the font, and make sure the CDN passes through or caches the header.

For an Apache origin, a configuration can look like this:

<IfModule mod_headers.c>
    <FilesMatch "\.(eot|otf|ttf|ttc|woff|woff2)$">
        Header set Access-Control-Allow-Origin "https://www.example.com"
    </FilesMatch>
</IfModule>

Replace the example origin with the website origin that loads the fonts. A wildcard value may also be appropriate for public font files when credentials are not involved. Nginx, IIS, and managed CDN services use different configuration methods.

If you cannot set the required response header, exclude the affected stylesheet or font path through Ignore Files so the browser loads it from the website origin.

The CDN still serves an old file

Purge or invalidate the file in the CDN provider. Pro can also add the local modification time to selected file URLs with File Versioning, causing a changed local file to use a new URL.