I Built a One File Edge Probe to Tell Me When Time Is Lying (physical-ai.ghost.io)

Note: This is a sanity probe, not a time discipline tool. rtt/2 and browser timers can be noisy, so treat green/red as a hint, not truth, especially on congested factory networks.

Interesting, but why not use the timestamp baked into response headers? There's also domain.tld/cdn-cgi/trace for cloudflare. I don't know how cloudflare will take using that page for this though.

A simple (and stupid) /time.aspx in VB.NET, because that's what was easily available:

    <%
    Dim epochMilliseconds As Long = CLng((DateTime.UtcNow - New DateTime(1970, 1, 1)).TotalMilliseconds)
    Response.Write("{ ""epoch_ms"": " & epochMilliseconds & " }")
    %>

(you need to change "/time" to "/time.aspx" for the original HTML page to work)