A Content Delivery Network (CDN) is a geographically distributed group of servers which work together to provide fast delivery of Internet content. A CDN allows for the quick transfer of assets needed for loading Internet content including HTML pages, javascript files, stylesheets, images, and videos.
CDNs reduce latency by serving content from an edge location close to the user rather than a central origin server. They also provide scalability to handle traffic spikes and absorb DDoS attacks, protecting the backend infrastructure.
A CDN is standard practice for any web-facing property. We rely on CDNs to offload static asset delivery. However, we are wary of "cache poisoning" and over-reliance on vendor-specific logic at the edge (e.g., complex VCL/Workers) that locks us into a specific provider.