Cool, thanks for taking a look! Do you know of any official reference for how the Cloudflare CDN server clocks are synced? I looked around but didn't find one.
I originally built the clock on Fastly, but they (appear to) have clock offsets of hundreds of milliseconds, so I didn't release that version. Cloudflare CDN seems synchronized better than what I can measure, although I'm wary of hard to test corner cases, like newly deployed servers.
Ooo, great find on the delay attack. I'll read up on that one today, but I think you're right.
The terms I'm using for this are web-native and a demo. Certainly not simple.
Hey, author here. You're asking a couple questions, which I'll try to unpack.
You're right to be suspicious that Cloudflare CDN servers have the right time. I tried to call out that concern in the post. Cloudflare operates time services, but their CDN is not a time service and wouldn't be operated under the same controls. How accurate those servers are is an open question.
When writing the post I observed NTP client logs, a GPS-based clock, and the CDN-based clock report time that agreed within their stated error bounds. I've also seen NTP-synchronized and mobile network synchronized system clocks that fell outside the estimates of those other clocks. So it's an "odd one out" situation.
But I think you are asking the right questions!
Any better source on this?
In theory, low-code, no-code, and LLMs would lower the effort needed but I think tinkering is a mindset. I think we need more tinkerers, so any efforts to encourage more have my support.
I use something I created, although it doesn't stack chores to the next day. I think everyone has a slightly different set of needs for a task tracking app, so if you are able, its worth creating your own.