What it checks
We time the gap between sending the request and receiving the first byte of the response, measured on the final hop after redirects, from our own server. It is a single sample from one location, so treat it as a smoke test, not a benchmark.
Why it matters for search engines
web.dev, which documents Google's page-experience metrics, treats a TTFB of 800 ms or less as good. TTFB caps every other loading metric: Largest Contentful Paint cannot happen before the first byte.
Why it matters for AI assistants
Crawlers have per-request timeouts. A slow origin is more likely to be cut off before the HTML arrives, and a crawler that gives up records nothing for that page.
How to fix it
Look at the layers in order: DNS, TLS handshake, then the origin's own response time. A CDN or cache in front of a slow origin fixes the first two and hides the third; fixing slow database queries or cold starts fixes the third.
First byte in 288 ms. Measured on the final hop, after redirects.What quietwatch reports
This check is always ok: we report the number, not a grade, because one sample from one location is not a verdict. Daily monitoring alerts when it changes by a large margin between runs.
Sources
All twelve checks · Previous: HTTP status · Next: Structured data