LazySizes is the more common of the two in our index: it runs on 3,212 websites against 166 for Cloudflare Zaraz, and 14 sites use both. Counts come from real scans, not vendor claims.
Cloudflare Zaraz gives you complete control over third-party tools and services for your website, and allows you to offload them to Cloudflare’s edge, improving the speed and security of your website.
LazySizes is a JavaScript library used to delay the loading of images (iframes, scripts, etc) until they come into view.
14 sites run both Cloudflare Zaraz and LazySizes. That is 8% of the sites using Cloudflare Zaraz, the smaller of the two.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.