CDN Guides are articles packed with information about one CDN feature. The Guide provides generic information and a handy CDN comparison table that provides quick and easy insight into how the feature is supported by/available on each CDN. You will also find more info/details per CDN including links to relevant external online sources.
Origin shield is an extra caching layer between the CDN servers and your origin.
CDN Guide: Origin shield
Origin very slow or down? CDN can still serve cached but expired responses.
CDN Guide: Serve stale
Invalidate or delete objects on the CDN. Just one object, all or by tag, key or header.
CDN Guide: Purge
Reduce file size, for faster responses and less bytes over the wire. Brotli?
CDN Guide: Compression