This document discusses re-using WebDriver-based tests for client-side performance analysis (CSPA). It covers the basics of CSPA, when to initiate CSPA, how CSPA relates to WebDriver tests, tools that can be used for CSPA including BrowserMob Proxy and dynaTrace, and examples of online services and desktop tools. References are provided for further information on CSPA and tools like YSlow, PageSpeed, GTmetrix and webpagetest.