Guides

Caching is one of the simplest ways to improve delivery. A cache saves a copy of a response so it can be served without a round trip to the origin. The core control surface is the Cache-Control header and the time-to-live (TTL). Freshness and validation determine when a cache can reuse a stored response and when it must contact the origin. Freshness vs validation A cache serves a response when it is fresh. Freshness comes from an explicit lifetime such as max-age or from an older Expires date. After freshness ends, a cache either revalidates or fetches again. ...

Why the choice matters A content delivery network (CDN) sits between an origin and clients. It handles caching, routing, and often security. The right provider improves performance and reliability, while the wrong fit can raise costs or limit flexibility. The choice depends on workload, geography, and operational model. Coverage and performance Global reach is uneven. A CDN strong in North America may be weaker in Africa or Southeast Asia. Map the audience by region and compare coverage there. Performance metrics such as latency and throughput matter, but so does stability under peak load. Independent measurement platforms can help validate claims. ...

Why HTTP/3 matters for CDNs HTTP/3 maps HTTP semantics onto QUIC, which uses UDP instead of TCP. The transport changes connection establishment, loss recovery, connection migration, and operational measurement at a CDN edge. Latency and connection setup QUIC integrates TLS 1.3 into its transport handshake. A full handshake permits application data after one round trip. A resumed connection can send 0-RTT application data when the client has suitable state from an earlier connection and the server accepts it. ...

What purging is Purging is the process of removing cached objects from a CDN. A purge tells the edge nodes that a file should no longer be served from cache. The CDN will then fetch a fresh copy from the origin the next time a client requests it. Purging differs from TTL expiry. TTLs control how long content is considered valid by default. Purges are active interventions to remove content before it would have expired. ...