A distributed network used to deliver website resources, which can reduce origin requests and delivery latency for suitably configured content.
A content delivery network, or CDN, distributes delivery across a network of servers. It can serve eligible content from locations that reduce the need for requests to reach the website’s origin server. The benefit depends on the network, the resource and how the site is configured.
A CDN does not make every request instant or remove every dependency on the origin. A resource may not be cached, a stored copy may need validation, or a page may contain personalized information that requires different handling. Treat the CDN as one part of delivery rather than a substitute for reliable hosting and correct application behavior.
For a business, the important questions are what the network serves, how content updates reach visitors and what happens when something fails. These questions matter as much as the provider name. A fast response containing yesterday’s pricing is still the wrong response.
Takeaway: Evaluate a CDN using the site’s actual resources and update workflow. Measure delivery and verify correctness rather than accepting promises of instant loading or complete protection from downtime.
Example
A photography business serves public portfolio images through a CDN while its booking application still needs current availability from the origin. Improving image delivery does not establish that the booking workflow is equally fast or resilient. The two parts need separate checks against their actual requirements.
What to check
Ask which files or responses are cached and how updates invalidate old versions. Test important public pages and interactive flows after configuration changes. Never assume that a CDN’s presence makes personalized or sensitive responses safe to share between visitors.
For more detail, see CDN: MDN glossary.