What is LCP by TTFB
LCP by TTFB shows the Largest Contentful Paint (LCP) values based on the Time to First Byte (TTFB) - the time it takes for the browser to receive the first byte of response from the server. This lens reveals how server performance influences the speed of loading your largest visible content.
Healthy LCP by TTFB sample
Should you worry
A healthy LCP by TTFB lens shows fast server responses paired with fast rendering. That means your backend is doing its job well - content is dispatched quickly and your users see something meaningful almost immediately.
Fast TTFB creates the foundation for a great LCP. Even if your front-end is well-optimized, the user’s experience starts with the server. If that’s slow, everything else is too.
Unhealthy LCP by TTFB sample
When TTFB is slow, LCP almost always suffers. You might see patterns like:
Good front-end, poor TTFB: The page structure is efficient, but it’s waiting for the server to respond — often caused by server-side rendering delays, routing overhead, or cold starts.
Poor TTFB and poor LCP: A compounded issue. The page takes time to start loading and is slow to fully display meaningful content.
These delays are especially problematic for first-time visitors, cold cache sessions, or users in distant regions.
Resolving unhealthy LCP by TTFB
Go-to action plan to resolve an unhealthy LCP by TTFB:
Ask Uxi to analyze your LCP by TTFB values and suggest improvements.
Use Filters to isolate sessions with Poor TTFB, then check for patterns in geography, device type, or page templates.
Simulate LCP of the suspected lens to see if fixing it will resolve the slow LCP by TTFB. If yes, this is where the resolution focus should be.
Use an automated LCP optimization tool like Navigation AI to improve your LCP by TTFB values.
Once you’ve improved LCP, set an alert to be the first to know if it starts worsening again.
Try it yourself
Discover how your website performs with real user data.