What is INP by FCP
INP by FCP shows how Interaction to Next Paint (INP) varies depending on the First Contentful Paint (FCP) — the moment the browser renders the first visible element.
FCP is the first “hello” from the browser. INP tells us how soon the site responds when users interact. When FCP is delayed, the user sees a blank screen for longer. When INP is slow, they see content but can’t engage. This lens reveals how early paint timing affects perceived interactivity.
Healthy INP by FCP sample
Should you worry
In a healthy INP by FCP lens:
Fast FCP sessions are paired with fast INP.
Users see something quickly and can interact with it promptly.
No misleading visual cues or "fake ready" UI states.
This suggests a seamless journey from seeing to doing — ideal for engagement and trust.
Unhealthy INP by FCP sample
Problems often look like:
Slow FCP, slow INP: The site is slow to show content and slow to react. This creates a perception of bloat and slowness — users might not even wait.
Fast FCP, slow INP: Looks like the page is ready, but it isn’t interactive. This leads to rage clicks and abandoned taps — the classic "it looks ready but it isn’t" trap.
Slow FCP, fast INP: Rare but possible — may indicate a light site where first paint is delayed due to late styling or fonts, but scripting is efficient.
Use this lens to spot where “looking ready” and “being ready” fall out of sync.
Resolving unhealthy INP by FCP
Go-to action plan to resolve an unhealthy INP by FCP:
Ask Uxi to analyze your INP by FCP values and suggest improvements.
Use Filters to isolate sessions with FCP/INP mismatch and explore common thread layouts or scripts.
Simulate INP of the suspected lens to see if fixing it will resolve the INP by FCP. If yes, this is where the resolution focus should be.
Use an automated INP optimization tool like INProve to improve your INP by FCP values.
Once you’ve improved INP, set an alert to be the first to know if it starts worsening again.
Try it yourself
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