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HTTP Timing Probe: TTFB, DNS, TLS Phases
Repeated timed GETs against an https URL: TTFB, totals, and Resource Timing phase splits.
https only: browsers block mixed content.
Browser egress
The browser fetches the URL you name, once per attempt, and reads its own Resource Timing entry for the phase split. This page leaves your browser only when you press the button; never on load, never in the background. Nothing is sent anywhere else, and no analytics loads on this page.
Wall-clock TTFB and total come from the fetches themselves; DNS/TCP/TLS splits come from Resource Timing. Cross-origin servers without Timing-Allow-Origin withhold them, the sample says so instead of showing zeros as truth.
Nothing in yet
Paste, drop, or type to begin. Everything stays on this device.