Are you measuring what matters? A fresh look at Time To First Byte

This post critically examines Time To First Byte (TTFB) as a performance metric, arguing for its limitations and advocating for Real User Monitoring (RUM) metrics like Core Web Vitals (Largest Contentful Paint, First Input Delay, Cumulative Layout Shift) as more accurate indicators of user experience. It details how TTFB fails to capture the complexity of modern web page loading, including render-blocking resources and the benefits of HTTP/2 and HTTP/3 multiplexing. Cloudflare's own performance optimization features, such as Zaraz, Rocket Loader, and image optimization, are highlighted as contributing to better RUM scores rather than solely impacting TTFB.