What does the TTFB check measure?
It measures the time from the request being sent to the first byte of the response arriving — the delay before anything can start rendering. This covers:
- Server processing — how long the backend takes to build the page (database queries, application logic).
- Network and connection — DNS, connection setup and the round trip to the server.
- Caching and delivery — whether responses are cached or served from a CDN edge close to the user.
A fast TTFB (roughly under 800 ms, ideally under 200) passes; a moderate delay is a warning; a slow response that holds up rendering is a fail.
How is it evaluated, and how is it scored?
GEObubbly requests the page and measures how long the server takes to return the first byte. It's a core, scored Performance check that runs partially, since the measured time depends on live server and network conditions at the moment of the request.
Why server response speed matters for SEO and GEO
TTFB is the foundation everything else is built on: until the first byte arrives, the browser can't download resources, render content or respond to the user. A slow TTFB therefore caps your best possible LCP and overall loading speed — you can optimise images and scripts all you like, but the page still can't start until the server replies. Slow responses usually trace back to unoptimised backend code, slow database queries, missing caching, underpowered hosting, or serving every request from a single distant origin instead of a CDN edge. The fixes are correspondingly direct: cache rendered pages or fragments, optimise slow queries, use a content delivery network so responses come from a server near the user, and choose hosting that matches your traffic. For crawlers, a fast server means more pages crawled per visit; for users, it's the difference between a page that feels instant and one that hangs.