About the Server Response Time Test
The Server Response Time Test measures the network layer of a URL with real connection instrumentation: DNS lookup, TCP connect, TLS handshake, time-to-first-byte and download rendered as a waterfall, plus HTTP protocol version, compression in use and document weight.
TTFB is the metric your hosting and backend control directly — if it is slow, no amount of frontend optimization will save the experience. Fix server response first, then audit tags with the Meta Tag Analyzer.
Time To First Byte measures how long the server needs before the first byte of the response arrives — DNS, connection, TLS and server processing combined. Under 200 ms is excellent, under 500 ms is fine, above 800 ms hurts both users and crawl budget.
Gzip or Brotli compression typically shrinks HTML, CSS and JS by 60–80%, directly cutting transfer time. This test sends an Accept-Encoding header and reports which compression the server actually used.
No — Lighthouse renders the page in a browser and scores Core Web Vitals. This test measures the raw network and server layer (DNS, connect, TLS, TTFB, download, weight), which is where slow TTFB and missing compression are diagnosed fastest. Both views complement each other.