What are MaxInstances Properties in Selenium Grid? MaxInstances is defined as the number of browser instances of the same version of the browser that can run on the remote machine. for eg. -browser browserName=InternetExplorer,version=11,maxInstances=3,platform=WINDOWS -browser browserName=Firefox,version=12,maxInstances=2,platform=WINDOWS This will allow running 5 instances (3 instances of IE and 2 instances of Firefox) at the same time on a remote machine.All Rights Reserved