What is TTFB by session duration
TTFB by session duration lens shows how Time to First Byte (TTFB) performs across different session lengths. It reveals how fast your server responds to requests for users who stay briefly vs. those who stay longer.
TTFB measures the time between the request for a resource and the first byte of the response. It’s a key server-side performance metric.
TTFB by session duration sample
Should you worry
A green TTFB across durations shows fast server responses for all users — even those who leave quickly. This suggests a consistent backend or CDN setup.
Unhealthy TTFB by session duration sample
High TTFB in 0s or 30s sessions may cause users to bounce before the page even starts rendering. High TTFB in long sessions could mean dynamic content or authenticated user flows are slowing down subsequent views.
Resolving unhealthy TTFB by session duration
Go-to action plan to resolve an unhealthy TTFB by session duration:
Ask Uxi to analyze your TTFB by session duration values and suggest improvements.
Filter by slow durations and review route or database latency.
Simulate TTFB of the suspected lens to see if fixing it will resolve the TTFB by session duration. If yes, this is where the resolution focus should be.
Use an automated optimization tool like Navigation AI to improve your TTFB by session duration values.
Once you’ve improved TTFB, set an alert to be the first to know if it starts worsening again.
Try it yourself
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