Web

Web performance

Terms

7 terms

  • CLS

    CLS, or Cumulative Layout Shift, is the Core Web Vital that measures how much visible page content moves unexpectedly while a user views it.

  • FCP

    FCP (First Contentful Paint) measures how long a page takes to render its first text or image, an early loading signal in web performance.

  • INP

    INP, Interaction to Next Paint, is a Core Web Vital that measures how quickly a page visibly responds to clicks, taps and key presses.

  • Lazy loading

    Lazy loading is a web performance technique that defers images, iframes and code until they are needed, cutting initial page weight and work.

  • LCP

    LCP (Largest Contentful Paint) measures when the largest image or text block in the viewport renders; a good page reaches it within 2.5 seconds.

  • Speed Index

    Speed Index is a lab metric in web performance that measures how quickly the visible content of a page is painted during loading, in milliseconds.

  • TTFB

    TTFB, or time to first byte, is a web performance metric measuring the delay from starting navigation until the first byte of the response arrives.