--- title: CDN Monitoring: Cache Hit Ratio & Edge Latency description: CDN monitoring by WatchFor. Find out whether your edge is really caching or quietly hitting your origin: cache hit ratio, per-region edge performance, and alerts when caching breaks. Free global CDN analyzer — 20 locations, A+ to F health grade, no signup. canonical: https://watchfor.io/cdn-monitoring --- # CDN Monitoring: Is Your Edge Really Caching? A CDN that stops caching does not go down — it just quietly asks your origin for everything, and your bill and your latency go up while every dashboard stays green. WatchFor requests your URL three times in a row from 20 locations, reads what each edge actually did with it, and alerts you the moment caching breaks. Try it free, no signup, on the CDN Checker. [Get started for free](/auth/sign-up)[View pricing](/pricing) ## What CDN Monitoring Actually Measures Not just whether a CDN is in front of you — whether it is doing its job ### Three Requests, Not One One request can tell you the edge missed its cache. Only a second can tell 'not cacheable' from 'not cached yet'. Every check makes the requests it takes to see MISS → HIT → HIT — the shape of an edge working correctly. ### Cache Hit Ratio You Can Alert On A real number, per check and over 24 hours, that you can put a threshold on. When a deploy adds a cookie and your hit ratio falls from 96% to 4%, you hear about it in minutes instead of on next month's bandwidth invoice. ### Origin Fallback Detection A misconfigured CDN never returns an error. It just serves everything from your origin — slower for users, heavier for your servers, more expensive for you, and completely invisible to an uptime check. ### 20 Global Locations Across the Americas, Europe, Africa, Asia and Oceania. A cache that is broken only in São Paulo is invisible from anywhere else, and one machine can never see it. ### Which Edge Answered The point of presence that served each region, read from the provider's own headers — the RIX in a Cloudflare ray, the FRA56 in a CloudFront POP. When one region is slow, you can see whether it was even routed to a sensible edge. ### Regional Comparison, Not Fixed Thresholds Every location is compared against the median of comparable locations, not an arbitrary millisecond limit. A site that is evenly slow is not nagged; a single region four times slower than its neighbours cannot hide. ### Content Consistency Across Regions Response bodies are hashed after decompression, so brotli and gzip regions compare equal. Two different hashes on a static asset means two different files are being served — a partial purge, a stale edge, or origins on different builds. ### Explanations, Not Just Numbers Every finding says what was measured, what it probably means, and what to do about it — produced by fixed rules, never by a language model, so the same measurements always give the same answer. ## The Failure Nobody Gets Paged For Every other kind of outage announces itself. A CDN that stops caching does the opposite: the site stays up, every status code stays 200, and uptime monitoring stays green while every single request travels to your origin. You find out weeks later from a bandwidth bill, or never. That gap is what this monitor exists to close — it does not ask whether your site is up, it asks whether the edge is doing the one thing you pay it for. Start with the free CDN Checker to see where you stand right now, then put a monitor on the URLs that matter. [Start monitoring now](/auth/sign-up) Cache hit ratio as a number you can set an alert threshold on MISS → HIT → HIT verified, so a cold object is never mistaken for a broken one Origin fallback caught in minutes, not on the next invoice 20 probe locations across 7 regions Per-region edge identifiers, so you can see which PoP answered Regional medians instead of fixed thresholds — far fewer false alarms Content consistency checked by hashing bodies across regions Free global CDN Checker with an A+ to F health grade, no signup ## How CDN Monitoring Works Point it at a URL, not just a hostname 1 ### Give It the URL That Matters Caching rules are set per path far more often than per host. `/` may be uncacheable HTML while `/static/app.js` is cached for a year — so monitor the asset you actually care about, not just the apex. 2 ### It Requests It More Than Once Each check makes sequential requests on separate connections, so the cache verdicts stay independent and every request reports its own DNS, TCP, TLS and time-to-first-byte breakdown. 3 ### It Reads What the Edge Said Cloudflare's cf-cache-status, Akamai's TCP_MEM_HIT, CloudFront's Hit from cloudfront, Bunny's cdn-cache — each provider's own vocabulary, normalised so regions can be compared, with the original wording kept beside it. 4 ### It Tells You When That Changes Set a threshold on the hit ratio, on time to first byte, or on the provider itself. When caching quietly stops working, you get an incident with the numbers behind it — not a green dashboard. ## CDN Monitoring Use Cases Perfect for any content delivered from the edge ### Cache Configuration Validation Confirm new caching rules and TTL changes behave as intended after every deploy. Catch a rule that accidentally disables caching before it sends your traffic back to origin. ### Origin Load Protection Detect silent origin fallback the instant it starts. Keep your origin servers shielded from traffic floods that a misconfigured cache would otherwise unleash. ### Global Performance Assurance Measure edge response times from the regions your audience lives in. Spot a slow or degraded PoP so a regional slowdown never quietly hurts your users. ### Static Asset & Media Delivery Keep images, scripts, stylesheets, and video segments serving fast from the edge. Verify large media files stay cached and download quickly worldwide. ## Frequently Asked Questions Everything you need to know about CDN monitoring What is CDN monitoring? CDN monitoring continuously checks that your content is genuinely being delivered from your content delivery network's edge rather than fetched from your origin every time. It verifies cache hits, inspects cache and edge headers, and measures response times from multiple regions — so you know your CDN is accelerating delivery and not silently bypassing its own cache. Why is my CDN not caching? What is a good cache hit ratio? What is the difference between a cache HIT and a MISS? Can you detect when my CDN falls back to origin? Which CDN providers can I monitor? Why monitor my CDN from multiple locations? Do you render the page or measure Core Web Vitals? How often are CDN checks performed? Is there a free CDN checker? ## From our blog Guides, deep-dives, and best practices from the WatchFor team [Engineering ### Your CDN didn't go down. It stopped caching — and nothing told you. Sep 10, 2026·10 min readRead article](/blog/why-your-cdn-stopped-caching)[Performance ### What is a CDN? (And do you actually need one?) Apr 08, 2026·3 min readRead article](/blog/what-is-a-cdn)[Performance ### Caching Explained: browser, CDN and server caches Jan 19, 2026·3 min readRead article](/blog/caching-explained) ## See What Your Edge Is Actually Doing Run the free CDN Checker on any URL — 20 locations, three requests each, a graded report in seconds and no signup. If you like what it tells you, put a monitor on it and find out the next time it changes. [Get started for free](/auth/sign-up)[View documentation](/docs/monitors/performance#cdn) --- Canonical page: https://watchfor.io/cdn-monitoring · Site guide: https://watchfor.io/llms.txt