Server Response Time (TTFB)

Server Response Time, technically measured as Time to First Byte (TTFB), is the exact duration it takes for a user’s browser to receive the first byte of data from the web server after making an HTTP request. It is the foundational metric of page speed; if the server is slow to respond, every subsequent Core Web Vitals metric (like FCP and LCP) will fail. A slow TTFB is usually caused by inadequate web hosting, complex database queries, or bloated application logic. Achieving a TTFB of under 200 milliseconds requires premium hosting infrastructure, aggressive server-side caching, and a globally distributed CDN.

Server Response Time (TTFB) Simplified

Server Response Time is the delay between when you click a link and when the website’s computer actually starts sending data to your screen. If the server is slow, your entire website will be slow, which frustrates users and destroys your SEO rankings.