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Cache
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Cache
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  1. Products
  2. Cache / CDN
  3. Concepts
  4. Default cache behavior

Default Cache Behavior

Cloudflare respects the origin web server’s cache headers in the following order unless an Edge Cache TTL page rule overrides the headers.

  • Cloudflare does not cache the resource when:
    • The Cache-Control header is set to private, no-store, no-cache, or max-age=0.
    • The Set-Cookie header exists.
  • Cloudflare does cache the resource when:
    • The Cache-Control header is set to public and max-age is greater than 0. Note that Cloudflare does cache the resource even if there is no Cache-Control header based on status codes.
    • The Expires header is set to a future date.

Note: If both max-age and an Expires header are set, max-age will be used by Cloudflare.

For a list of directives and behaviors when Origin Cache-Control is enabled or disabled, refer to Cache-Control directives.

​​ Default cached file extensions

Cloudflare only caches based on file extension and not by MIME type. The Cloudflare CDN does not cache HTML by default. Additionally, Cloudflare caches a website’s robots.txt.
7Z CSV GIF MIDI PNG TIF ZIP
AVI DOC GZ MKV PPT TIFF ZST
AVIF DOCX ICO MP3 PPTX TTF
APK DMG ISO MP4 PS WEBM
BIN EJS JAR OGG RAR WEBP
BMP EOT JPG OTF SVG WOFF
BZ2 EPS JPEG PDF SVGZ WOFF2
CLASS EXE JS PICT SWF XLS
CSS FLAC MID PLS TAR XLSX

To cache additional content, refer to Page Rules to create a rule to cache everything.

​​ Customization options and limitations

Cloudflare’s CDN provides several cache customization options:

Cloudflare limits the upload size (HTTP POST request size) per plan type:

  • 100MB Free and Pro
  • 200MB Business
  • 500MB Enterprise by default. Contact Customer Support to request a limit increase.

If you require a larger upload, group requests smaller than the upload thresholds or upload the full resource through an unproxied (grey-clouded) DNS record.

Cloudflare cacheable file limits:

  • Free, Pro and Business customers have a limit of 512 MB.
  • For Enterprise customers the default maximum cacheable file size is 5 GB. Contact your account team to request a limit increase.

​​ Cloudflare cache responses

The output of the CF-Cache-Status header shows whether or not a resource is cached. To investigate cache responses returned by the CF-Cache-Status header, use services like Redbot, webpagetest.org, or a visual tool like Chrome’s Dr. Flare plugin.

Status Description
HIT The resource was found in Cloudflare’s cache.
MISS The resource was not found in Cloudflare’s cache and was served from the origin web server.
NONE/UNKNOWN Cloudflare generated a response that denotes the asset is not eligible for caching. This may have happened because:
  • A Worker generated a response without sending any subrequests. In this case, the response did not come from cache, so the cache status will be none/unknown.
  • A Worker request made a subrequest (fetch). In this case, the subrequest will be logged with a cache status, while the main request will be logged with none/unknown status (the main request did not hit cache, since Workers sits in front of cache).
  • A Firewall rule was triggered to block a request. The response will come from the edge network before it hits cache. Since there is no cache status, Cloudflare will log as none/unknown.
  • A redirect page rule caused the edge network to respond with a redirect to another asset/URL. This redirect response happens before the request reaches cache, so the cache status is none/unknown.
    		•
    EXPIRED The resource was found in Cloudflare’s cache but was expired and served from the origin web server.
    STALE The resource was served from Cloudflare’s cache but was expired. Cloudflare could not contact the origin to retrieve an updated resource.
    BYPASS The origin server instructed Cloudflare to bypass cache via a Cache-Control header set to no-cache,private, or max-age=0 even though Cloudflare originally preferred to cache the asset. BYPASS is returned when enabling Origin Cache-Control. Cloudflare also sets BYPASS when your origin web server sends cookies in the response header. If the Request to your origin includes an `Authorization` header, its response will be also BYPASS.
    REVALIDATED The resource is served from Cloudflare’s cache but is stale. The resource was revalidated by either an If-Modified-Since header or an If-None-Match header.
    UPDATING The resource was served from Cloudflare’s cache and was expired, but the origin web server is updating the resource. UPDATING is typically only seen for very popular cached resources.
    DYNAMIC Cloudflare does not consider the asset eligible to cache and your Cloudflare settings do not explicitly instruct Cloudflare to cache the asset. Instead, the asset was requested from the origin web server. Use Page Rules or Cache Rules to implement custom caching options.