What does CloudFlare cache?
Cloudflare caches static content depending on:
- where your visitors come from,
- which Cloudflare data center your visitors reach, and
- how often visitors request a resource at the specific data center.
Cloudflare only caches a resource within the Cloudflare data center that serves the request and doesn’t cache:
- off-site or third-party resources (Facebook, Flickr, etc), or
- content hosted on unproxied (grey-clouded) DNS records.
CloudFlare provides detailed information on their caching system in their documentation here.