The Time To First Byte (TTFB), or server response time, of your WordPress site can be an important indicator of performance. It doesn’t represent the whole picture, but a very specific part in the process.
Time to First Byte is a measure of how fast your server responds when someone tries to visit a page on your site. Specifically, it’s measuring how long it takes from the time the browser asks the server for the page, to when the browser receives the first piece of data from the server.
Visitors want sites to feel fast, so the sooner some meaningful content is displayed on the screen, the better. TTFB can influence this – the faster the server responds, the faster content can get to the user.