Next.js Speed Insights allows you to analyze and measure the performance of pages using different metrics.
You can start collecting your Real Experience Score with zero-configuration on Vercel deployments.
The rest of this documentation describes the built-in relayer Next.js Speed Insights uses.
Web Vitals are a set of useful metrics that aim to capture the user experience of a web page. The following web vitals are all included:
- Time to First Byte (TTFB)
- First Contentful Paint (FCP)
- Largest Contentful Paint (LCP)
- First Input Delay (FID)
- Cumulative Layout Shift (CLS)
- Interaction to Next Paint (INP) (experimental)