BLOGS

A CDN is most useful when it can reuse the same response for many visitors. Public images and versioned stylesheets are straightforward candidates. Customer panels require more care because the response can depend on identity, permissions and recent account activity.

Classify routes before creating rules

Write a short inventory of public content, personalized pages and state-changing actions. Include login, logout, password reset, cart, checkout and account endpoints. Do not assume a page is public simply because its URL looks ordinary; inspect how the application chooses the response.

Understand the cache key

A shared cache must distinguish responses that are meaningfully different. Query parameters, request headers and cookies can influence content, but the exact cache key and bypass behavior depend on configuration. The NGINX proxy module reference documents its cache-key and bypass controls. Verify your own CDN's behavior rather than copying rules between products.

For private account responses, establish explicit caching controls at the origin and compatible rules at the edge. A broad cache-everything rule can undermine the intended behavior. Never test private-page separation using real customer accounts whose information might be exposed.

Test two identities and a guest

Use dedicated test accounts with clearly different sample content. Request the same account URL as the first account, then the second, then as a signed-out visitor. Verify both the displayed data and relevant cache response headers. Repeat after logout and after a change to the account data. This catches errors that a single-account test misses.

Plan content updates

Version public asset filenames when their contents change. For content that keeps the same URL, define an expiration and invalidation strategy. Test the first uncached request after a purge as well as cache hits; an origin must cope with requests that cannot be served from the edge.

Track cache effectiveness and origin load alongside correctness. A high hit rate is not a success if it serves the wrong response. For additional caching concepts, consult NGINX's content caching guide. Size your origin server for the dynamic workload that remains.