Vary for images

Vary is an HTTP response header that allows origins to serve variants of the same content that can be used depending on the browser sending the request.

Cloudflare sits in between the browser and the origin. When Cloudflare receives the origin’s response, the specific image variant is cached so that subsequent requests from browsers with the same image preferences can be served from cache. This also means that serving multiple image variants for the same asset will create distinct cache entries.

Vary for Images reduces the content-negotiation process by parsing a request’s Accept header, which is sent to the origin to deliver the correct content to the browser.

Vary for images is available for Pro, Business, and Enterprise customers.

​​ Availability

​​ File extensions

You can use vary for images on the file extensions below if the origin server sends the Vary: Accept response header. If the origin server sends Vary: Accept but does not serve the set variant, the response is not cached and displays BYPASS in the cache status in the response header. Additionally, the list of variant types the origin serves for each extension must be configured so that Cloudflare decides which variant to serve without contacting the origin server.

To begin using Vary for Images, refer to Enable Vary for Images. To learn more about purging varied images, refer to Purge varied images.

​​ Limitations

• For Vary for images to work, your image URLs must include the file extension in the path and not the query string. For example the URL https://example.com/image.jpg is compatible but https://example.com?index.php?file=image.jpg is not compatible.
• Your origin must return an image type matching the file extension in the URL when a HTTP client sends no Accept header, or an Accept: */* header. Otherwise, you will see CF-Cache-Status: BYPASS in the HTTP response headers.