The tool only detects a subset of paid Cloudflare users - specifically those with the default ECH settings. If your site shows as undetermined, it likely means you're on a free plan or a paid plan with ECH enabled.
From what I've observed:
- Free plans: ECH is forcefully enabled (sni=encrypted)
- Paid plans: ECH is disabled by default (sni=plaintext), but can be manually enabled
The tool can only definitively distinguish between free plans and paid plans that use the default ECH settings.
There are occasional false positives, but querying different Cloudflare data centers usually resolves this. I've found that switching VPN servers (which routes through different CF edge locations) eventually gives the correct result.
Thanks for your response. I ran a test but I'm not sure if it's working as expected. I performed a Google search on my mobile device for "inurl:amp.cnn.com." However, when I clicked on a result, the page I saw did not appear to use AMP--it redirected me to edition.cnn.com instead.
I published the repository with source code of the demo. The README contains detailed explanation how the demo works as well as instructions on how to host the demo yourself.
You're right: the site is SXG-enabled, and the point of the demo is to show that Google can prefetch and serve it even when you're offline — but only if you search for a specific phrase on Google. Random searches won’t trigger the right preload.
The 4-digit code is intentionally hardcoded — it's not a security check, but a way to make sure the user follows the instructions and gives Google a bit more time to prefetch the content before going offline.
The progress bar also helps with timing — making sure the preload has a chance to complete.
After reading your comment, I added a link to a blog post in the final step of the instructions, in case the demo doesn't work as expected. (If the page is cached from an earlier visit, a refresh helps — it's got a long browser cache.)
Thanks for the detailed feedback — really appreciate it!
You're right that the demo relies on Google Search specifically (not DuckDuckGo), and that should probably be made even clearer in the instructions. I do mention “search Google” in step 3, but I’ll look into making that more explicit up front.
As for airplane mode: the idea is to go offline after Google has had time to prefetch the page. That’s why the instructions say to start with a stable internet connection — and the page does show a warning if you go offline too early. But I totally get how that could still be confusing, especially if it didn’t work the first time.
A tip: once you're on the "You're offline" page, wait at least 3 seconds and observe the dinosaur. Something may happen.
And good point about wanting to know what’s going on. I tried to keep the experience surprising for some users, but I see how having the technical context up front can enhance it for others. I’ll consider adding an “explain first” option in the future.
The key difference from AMP is that the site signs the content and it’s attributed to their origin, not Google’s. So, while it’s served from Google’s cache, it still counts as the publisher’s page in terms of origin and trust.
I skipped technical terms like “prefetch” or “SXG” in the title to make it more approachable and spark curiosity — but I get how that could feel misleading.
You're right that prefetching counts as a visit in some sense. The point of the demo was to highlight how unexpected it can feel to load a site while offline, even if you never actively opened it before.
The demo uses 2 html pages - one for instructions, the second one for the actual site that is prefetched. But maybe I will create a repo with it.
HN is a perfect candidate to integrate Signed Exchanges - it's a link aggregator, the type of website SXG authors have in mind while designing this standard.
From what I've observed:
- Free plans: ECH is forcefully enabled (sni=encrypted)
- Paid plans: ECH is disabled by default (sni=plaintext), but can be manually enabled
The tool can only definitively distinguish between free plans and paid plans that use the default ECH settings.