CDN Guides are articles packed with information about one CDN feature. The Guide provides generic information, a handy CDN comparison table showing which CDNs have the feature and more info per CDN including links to relevant external online resources.
Serve Stale
Serve Stale means the CDN serves expired objects from cache while the origin is slow, down or returns errors.
Prefetch
Prefetching is warming the CDN caches, so first users don't get a slow cache miss response. Relevant for large file/video delivery.
Purge
Invalidate or delete objects on the CDN. Just one object, all or by tag, key or header.
Compression
Compression (Gzip, Brotli) greatly reduces file size, for faster responses and less bytes over the wire.
Origin Shield
Origin Shield is an extra caching layer between the CDN servers and your origin.