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The Fetch compressed option tells CDN servers to pull already-compressed content from the origin instead of requesting uncompressed files. The origin must support GZip compression.

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Configure Fetch compressed

To enable the option, open the resource settings in the Customer Portal.
  1. In the Gcore Customer Portal, navigate to CDN. The CDN resources page opens.
  2. Click the CNAME of the resource to open its settings.
  3. Open the OPTIONS tab and scroll to the Content section. Click Fetch compressed in the left sidebar.
  4. Turn on the Enable fetch compressed toggle.
Fetch compressed section in CDN resource settings with the Enable fetch compressed toggle
  1. Click Save changes.
If the origin compresses content with Brotli, the CDN receives uncompressed content when Fetch compressed is enabled. To deliver Brotli-compressed content through the CDN, configure the origin to send a Brotli file when the CDN requests a GZip-encoded response.

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Behavior when enabled

When Fetch compressed is active, CDN servers treat the origin as the source of truth for content encoding.
  • CDN servers do not decompress fetched content before delivering it to end users. End users receive compressed content regardless of whether the browser accepts compression.
  • Fetch compressed and GZip compression cannot be active simultaneously — enabling one disables the other.

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Compression without CDN settings

When Fetch compressed and other CDN compression options are disabled, compression can be controlled by the origin server using Accept-Encoding, Content-Encoding, and Vary headers. Compression behavior then depends on whether the origin supports it.

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Origin supports compression

To deliver either compressed or uncompressed content per request, disable all compression settings on the CDN resource. Then configure two HTTP headers on the origin server: Vary: Accept-Encoding and Content-Encoding. CDN servers check the Accept-Encoding header in every request from end users. If the header includes gzip, deflate, or br, the CDN requests the compressed version from the origin. If those directives are absent, the CDN requests the uncompressed version.
  • If Vary: Accept-Encoding is not set on the origin server, CDN caches the first version it receives — compressed or uncompressed. A user who needs the other version will receive the cached copy, which the browser may fail to display correctly.
  • If Vary: Accept-Encoding is set, CDN caches both versions separately and serves the correct one per request.

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Origin does not support compression

CDN stores the uncompressed file. End users receive the uncompressed version regardless of whether the request includes compression headers.