Real visitors using Chrome find the website slow to load, slow to respond or jumpy, by Google’s own measures. Poor page experience can cost rankings and conversions.
What it means
Core Web Vitals are three measures of what visitors actually experience: Largest Contentful Paint (how fast the main content appears), Interaction to Next Paint (how fast the page reacts to a tap or click) and Cumulative Layout Shift (how much the page jumps around). At least one is rated poor.
What triggers it
Once a day, as part of Uptime monitoring, SaaSMaestro reads the whole website’s figures from the Chrome UX Report, covering the last 28 days. It needs a Chrome UX Report API key on the Data connections tab. Following Google, a metric is poor when more than a quarter of visits are worse than 4 seconds for LCP, 500 ms for INP or 0.25 for CLS. Any poor metric raises a Medium issue.
Common causes
- Large images, slow hosting or render-blocking scripts and fonts (LCP).
- Heavy JavaScript, such as chat widgets, tag managers and ad scripts (INP).
- Images, ads or banners without reserved space, and late-loading fonts (CLS).
How to fix it
- Run PageSpeed Insights on the busiest pages and note which metric is poor.
- Fix the largest causes it lists first: compress images, defer or remove scripts, and reserve space for content that loads late.
- Watch the weekly lab score to confirm the fix before real-visitor figures catch up. See Slow in Google’s lab test.
When it clears
The issue goes once no metric is rated poor. Because the figures cover 28 days, a fix can take up to four weeks to show fully.
After 7 days without the problem, the action drops off the board. If you marked it done and the problem is still detected 14 days later, it returns as “Fix didn’t work”.