Cloudflare makes customer websites faster by storing a copy of the website’s content on the servers of our globally distributed data centers. Content can be either static or dynamic: static content is “cacheable” or eligible for caching, and dynamic content is “uncacheable” or ineligible for caching. The cached copies of content are stored physically closer to users, optimized to be fast, and do not require recomputing.
Cloudflare caches static content based on the following factors:
- Cache level set at a zone or
- File extension
- Presence of query strings
- Origin cache-control headers
- Origin headers that indicate dynamic content
- Page rules that bypass cache on cookie
Cloudflare only caches resources within the Cloudflare data center that serve the request. Cloudflare does not cache off-site or third-party resources, such as Facebook or Flickr, or content hosted on DNS records.