Time to first byte (TTFB)

Time to first byte (TTFB) is a measurement used as an indication of the responsiveness of a webserver or other network resource.

TTFB measures the duration from the user or client making an HTTP request to the first byte of the page being received by the client’s browser. This time is made up of the socket connection time, the time taken to send the HTTP request, and the time taken to get the first byte of the page.