Core Web Vitals and CDNs: LCP, INP and what the edge can fixCore Web Vitals are field measurements from real users. If those users are not next to your origin, LCP is a geography score until you put HTML and the LCP image on an edge.
How to reduce TTFB with a CDN and better DNSTTFB is the wait before the first byte of the response. People blame PHP, then ship a bigger origin. For global visitors the wait is often geography: a lookup in one continent and an origin in another.- Static vs dynamic content on a CDNStatic means the bytes are the same for every anonymous visitor. Dynamic means the origin ran code. A surprising amount of dynamic output is still shareable — and that is the traffic a CDN should keep.
CDN vs reverse proxy: what each layer is fornginx, Caddy, HAProxy and cloud load balancers are reverse proxies. They terminate TLS, route paths and sometimes cache — in one region. A CDN does related work at 210+ locations, with purge, Anycast and origin protection as the product.- What is a point of presence (PoP) in a CDN?A point of presence is a place the network can answer from. In a CDN it is where TLS terminates, cache lives and — on a miss — the origin is pulled. More PoPs only help if they are actually on the path your users take.
Cache-Control headers, explained for CDN operatorsBrowsers and CDNs both read cache headers, but they are not the same audience. A page that is private for a browser can still be a disaster if the CDN treats it as public. Set headers on purpose, then let Cloud CDN honour or override them with distribution policy.- How DNS works, from resolver to authoritative answerEvery page view starts with a lookup. The browser asks a recursive resolver; that resolver asks (or remembers) your authority. The TTL on the last answer decides how long the world will keep using it.
- What is authoritative DNS?Authoritative DNS is the service that owns your zone. When a recursive resolver asks what www.example.com is, the nameservers you delegated are supposed to know. If they are slow, attacked or stuck on a high TTL, nothing else on the site matters.
How to migrate to a CDN without downtimeCDN migrations fail on DNS and cache policy, not on the first byte of a test file. The origin can stay where it is. The public hostname should move only after the distribution has been proven.- How to choose a CDN: a practical checklistCDN marketing lists features. Production lists failures: a purge that did not land, an origin that melted on TTL expiry, a checkout cookie that got cached, a certificate that expired on one hostname. Choose against that list.
How a CDN works: request path, cache hits and origin missesA CDN looks simple from the outside — files feel closer — but the request path has three distinct jobs: receive, evaluate and deliver. Understanding those jobs is how you set TTLs, bypass rules and purge without surprises.- What is a CDN? Content delivery networks explainedA content delivery network (CDN) is a distributed cache in front of your origin. Instead of every browser, app or downloader opening a connection to one server, a nearby point of presence answers with a stored copy — or fetches once and then reuses that copy.