Selenium Server

Selenium Server allows us to run tests on browser instances running on remote machines and in parallel, thus spreading a load of testing across several machines. We can create a Selenium Grid, where one server runs as the Hub, managing a pool of Nodes. We can configure our tests to connect to the Hub, which then obtains a node that is free and matches the browser we need to run the tests. The hub has a list of nodes that provide access to browser instances, and lets tests use these instances similarly to a load balancer. Selenium Grid enables us to execute tests in parallel on multiple machines by managing different types of browsers, their versions, and operating system configurations centrally.