Above the Fold
This is a term originally from newspaper design that now refers to the portion of a webpage that is visible to a user without having to scroll down. Content "above the fold" is the very first thing a user sees. Optimizing this area for speed is critical for making a good first impression and achieving a fast Largest Contentful Paint (LCP).
Related web performance terms
- A/B Testing
A/B testing is a method of comparing two versions of a webpage to see which one performs better. For example, an e-commerce store might show 50% of its visitors a green "Buy Now" button (Version A)…
- AVIF
AVIF (AV1 Image File Format) is a modern, next-generation image format that provides significantly better compression than older formats like JPEG and WebP.
- Abandonment Rate
Abandonment Rate is a metric that measures the percentage of users who start a specific process (like a checkout funnel or a sign-up form) but leave before completing it.
- Acceleration Rate
The acceleration rate is a key performance indicator specific to Speed Kit that measures the percentage of whitelisted page views that were successfully accelerated by the Service Worker.