AEM Dispatcher and CDN Caching: Keys, Invalidation and Freshness.

Classify public pages, content APIs, assets and user-specific responses before editing rules. The same caching assumptions should not be applied indiscriminately to every request served by the platform.

Ignoring an output-changing query parameter or reusing a private response can make caching incorrect even when it appears fast. Freshness and response identity are part of the design, not secondary performance checks.

Document the request path and the cache rules at each layer. A Dispatcher invalidation does not, by itself, prove that a separate CDN response is fresh; verify the configured relationship and expiration behavior.

Review which requests may reach AEM independently from which responses may be cached. For query parameters, ignore only values demonstrated not to affect the response; retain a deliberate policy for personalization and authenticated access.

• List expected cacheable URL shapes and response classes.
• Review invalidation rules alongside content publication behavior.
• Inspect actual response headers and cached responses at each boundary.

Compare responses for parameter variants and access states before changing cache policy. A convenient rule that merges distinct responses is a correctness defect, not a performance optimization.

Broad invalidation can cause avoidable origin work; narrow invalidation can leave dependencies stale if their relationships are not modeled. Choose a policy with explicit freshness expectations and test dependent pages.

When the failing layer is not yet known, start with evidence-led AEM production troubleshooting.

Use the same request fixtures across cache layers so the comparison is meaningful.

• Compare anonymous and authenticated behavior where applicable.
• Vary query parameters and confirm expected response identity.
• Publish an update and inspect delivery before and after invalidation or expiry.

Keep rules reviewable and attach a reason to each exception. This study defines a validation approach; it does not assert measured latency or cache-hit improvements.

These sources document product behavior. The design and validation approach above are engineering proposals, not claims made by the vendors.

• Adobe: Dispatcher configuration reference