AEM Cloud CDN compression needs a response test

Compression can disappear into a vague “CDN problem” when the request and response are not captured together. A recent AEM as a Cloud Service question reports gzip for one Accept-Encoding combination and an uncompressed response for another. The sensible next step is a reproducible response matrix, not an assumed CDN setting.

Measure the full delivery path

For representative HTML, CSS, JavaScript, and asset URLs, record request Accept-Encoding, response Content-Encoding, Content-Type, status, cache headers, host, and CDN layer. Compare cold and warm responses. Use byte counts from the transfer, not only an application bundle estimate.

Separate origin and edge behavior

Test the same resource through each supported route where possible. Note whether a custom CDN, dispatcher rule, or response header transformation is present. Adobe’s CDN documentation describes the managed edge and customer-managed alternatives; it should guide ownership of each layer.

Choose a change only after a benefit test

If a compression gap is repeatable, measure real transfer and render impact for the affected traffic. Raise the exact request/response pair with Adobe support before treating Brotli as a configurable switch. Preserve a rollback path if a customer-managed delivery layer is considered.

Adovo’s view

A performance decision starts with observed bytes and user time. A missing encoding label is a lead, not a strategy. Establish the route and measurable cost before adding complexity to the delivery stack.