The top website performance metrics are:
Page Load Time – Loading speed (also measured as “time to title” and “start render time”)
Time to Interact – The time takes before interactive elements, such as links are active.
Requests Per Second – The rate at which pages and their element are requested
Element Weight – The number of bytes each element in a web page represents (also look at asset type weight and overall weight)
Bounce Rate – The percentage of visitors who leave after viewing only one page
Error Rate – The number of load failures