Time to First Byte (TTFB)
Time to first byte measures how long it takes for a browser to receive the first byte of a page from the server after making a request. It captures server response time, network latency, and any redirects along the way.
Why It Matters
A slow TTFB delays everything that follows, dragging down Core Web Vitals and the perceived speed of the page. On paid landing pages a slow first byte raises bounce and lowers Quality Score.
Common Mistake
Optimizing images and scripts while ignoring a slow backend. If the server takes a second to respond, front-end tuning cannot compensate, and caching or a faster host is the real fix.