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Default cache behavior

Cloudflare respects the origin web server’s cache headers in the following order unless an Edge Cache TTL cache rule overrides the headers. Refer to the Edge TTL section for details on default TTL behavior.

• 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.
  • The HTTP request method is anything other than a GET.
• Cloudflare does cache the resource when:
  • The Cache-Control header is set to public and max-age is greater than 0.
  • The Expires header is set to a future date.

When Origin Cache Control is enabled on an Enterprise customer’s website, it indicates that Cloudflare should strictly respect Cache-Control directives received from the origin server. Free, Pro and Business customers have this feature enabled by default. For a list of directives and behaviors when Origin Cache-Control is enabled or disabled, refer to Cache-Control directives.

Clients can send range requests to be served from the cache using the Range header. Note that:

• If the origin response includes a Content-Length header, then the specified byte range will be returned with an HTTP 206 response.
• If the origin response does not include the Content-Length header, the cache will return the full content with an HTTP 200 response.

When multiple requests arrive simultaneously at a single Cloudflare data center for the same asset that is not in cache (a cache miss), Cloudflare uses a cache lock to avoid sending duplicate requests to your origin. Only the first request is forwarded to the origin to fetch the asset. The remaining requests wait for the first request to complete, after which the response is streamed ↗ to all waiting requests.

The cache lock ensures that Cloudflare only sends one request at a time to the origin for a given asset from a single location in Cloudflare's network, preventing the origin from receiving excessive traffic.

Cloudflare only caches based on file extension and not by MIME type. The Cloudflare CDN does not cache HTML or JSON by default. Additionally, by default Cloudflare caches a website's robots.txt.

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

By default, Cloudflare caches certain HTTP response codes with the following Edge Cache TTL when a cache-control directive or expires response header are not present.

All other status codes are not cached by default.

Cloudflare’s CDN provides several cache customization options:

• Caching behavior for individual URLs via Cache Rules

• Customize caching with Cloudflare Workers
• Adjust caching level, cache TTL, and more in the Caching page in the Cloudflare dashboard:

Customers can reduce the Maximum Upload Size from the zone's Network page.

If you require a larger upload, you can group requests into smaller chunks, upload the full resource through a DNS-only (unproxied) DNS record or upgrade your plan.

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.

The connection status between visitors and Cloudflare can vary, affecting whether Cloudflare caches the content or not. If Cloudflare has already established a connection to the origin and started fetching the content, it will continue to retrieve and cache the entire content, even if the visitor disconnects midway. However, if a visitor disconnects before the origin responds to Cloudflare's request, no content will have been fetched yet, so Cloudflare will not start caching the content.