Slow server response time (TTFB)
High priorityPerformance
The server took more than 800ms to start sending the page.
What triggers this issue
- Response time 800–1800ms (warning).
- Response time over 1800ms (error).
Why it matters
Nothing can appear until the HTML arrives, so a slow server delays every other metric. Google suggests a time to first byte of 0.8 seconds or less.
We measure from our servers and take the faster of two requests to smooth out network noise.
How to fix it
- Turn on full-page caching in your CMS or framework.
- Serve the site through a CDN that caches HTML at the edge.
- Upgrade underpowered hosting and look for slow database queries or plugins.