Core Web Vitals (CWV) are a set of three specific, user-centric ranking signals introduced as part of Google’s Page Experience update in 2021. They measure the performance and experiential quality offered by a website:
- Largest Contentful Paint (LCP): Measures the time it takes for the largest visual content element to become visible within the user’s viewport, indicating perceived page loading speed.
- First Input Delay (FID): Measures a page’s responsiveness to user input events (like clicks or taps) during the loading phase. Note: FID is being replaced by INP (Interaction to Next Paint).
- Cumulative Layout Shift (CLS): Measures the stability of a page’s elements by quantifying how much elements unexpectedly move around upon loading, impacting user experience.
