Estimate Origin Revalidations From CDN Traffic

How to Use This Tool

Separate cache hits that still require validation from true origin-free responses. A high cache-hit ratio can still produce heavy origin traffic when objects repeatedly become stale and validate.

Why CDN Revalidations needs more than a raw total

A 304 response saves bytes but still consumes an origin request and latency path. For this page, the useful comparison is origin revalidation requests, not whichever input happens to be largest. The CDN Revalidations result answers the decision in the heading and should not be reused as a score for a different workflow.

The exact CDN Revalidations formula

Revalidations equal daily requests × cache-hit share × stale-hit share × days. The visible fields are Requests per day, Cache-hit share, Hits requiring revalidation and Days. For CDN Revalidations, read each printed unit before entry and make the values describe one transaction, cohort or reporting window. If those scopes differ, the displayed origin revalidation requests may be arithmetically valid but operationally meaningless.

Interpreting origin revalidation requests

Tune freshness by content class and verify validator behavior before extending TTL globally. The ten-percent comparison is deliberately narrow: it tests the influence of requests per day and is neither a forecast nor a confidence interval. Preserve the values used, their dates and the resulting decision so a later reviewer can reproduce why CDN Revalidations supported the choice.

What this CDN Revalidations model leaves out

Collapsed forwarding, stale-while-revalidate and regional cache keys are excluded. That is where CDN Revalidations stops being trustworthy. If an excluded factor could reverse origin revalidation requests, extend the model explicitly or use the authoritative account system instead of hiding the factor inside an unexplained adjustment.

Evidence and independent verification

The reference reviewed for CDN Revalidations is MDN — HTTP caching. MDN — HTTP caching supports the named definition or rule but does not supply private values for origin revalidation requests. Before acting on the result, reconcile the worked example with the relevant dashboard, invoice, export or measurement.

Private, reproducible calculation

CDN Revalidations runs its arithmetic in the current browser tab and requests no login or API key. That keeps the CDN Revalidations inputs away from the site's calculation server, while leaving the user responsible for detecting stale data or a changed platform rule. When an assumption changes, reopen MDN — HTTP caching and rerun the saved CDN Revalidations scenario.