Edge Cache Expire TTL is a parameter for the cache everything setting in a Page Rule
that controls how long Cloudflare's edge servers will cache a resource before getting back to your server for a fresh copy.
Sometimes cache headers are set on the server-side or by a CMS solution like Wordpress. If you choose to Cache Everything, you can set the Cache Everything rule to respect existing headers, which tells our edge nodes to hold the item in the cache for the time specified by the origin. If no headers are specified at the origin for the resource, our edge nodes will still cache the resource as long as that resource is frequently requested. It is important to note that the Edge Cache expire TTL isn't visible in response headers, but is an internal value recorded at our edge nodes.
To change the Edge Cache expires TTL, choose a time from the drop-down menu. This is the refetch time for when Cloudflare checks the origin server for a new resource.
Cloudflare offers a range of edge cache TTLs by plan type:
Free 2 hours
Pro 1 hour
Business 30 minutes
Enterprise as low as 30 seconds
Common situations where you may choose to set a Cache Everything rule:
- You expect a large surge in traffic
- You are under DDOS attack
- You are not sure what the headers on WordPress or your server are set to
- You are using WordPress and want to easily overwrite the default settings