> ## Documentation Index
> Fetch the complete documentation index at: https://gcore-doc-1894.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Configure fetch compression

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.

## Configure Fetch compressed

To enable the option, open the resource settings in the Customer Portal.

1. In the [Gcore Customer Portal](https://portal.gcore.com), 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.

<Frame>
  <img src="https://mintcdn.com/gcore-doc-1894/D4afn3gx_zp92kAa/images/docs/cdn/cdn-resource-options/compression/configure-fetch-compression/configure-fetch-compression-image1.png?fit=max&auto=format&n=D4afn3gx_zp92kAa&q=85&s=2b0c290cd86fca3cbbd95edd700d2984" alt="Fetch compressed section in CDN resource settings with the Enable fetch compressed toggle" width="1400" height="900" data-path="images/docs/cdn/cdn-resource-options/compression/configure-fetch-compression/configure-fetch-compression-image1.png" />
</Frame>

5. Click **Save changes**.

<Info>
  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.
</Info>

## 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](/cdn/cdn-resource-options/compression/configure-gzip-and-brotli-compression#gzip) cannot be active simultaneously — enabling one disables the other.

## 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.

### 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.

### Origin does not support compression

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