TimeToFirstByte(TTFB) is anITimingInfo object, It is the duration from the virtual user making an HTTP request to the first byte of the page being received by the browser. This time is made up of the socket connection time, the time taken to send the HTTP request and the time to taken to get the first byte of the page. TTFB is a measurement that is often used as an indication of the responsiveness of a webserver or other network resources.