Selenium Grid allows you to run tests on different machines (Nodes) against different browsers simultaneously. It uses a 'Hub' to receive test requests and route them to the appropriate 'Node'. Grid consists of: 1. Hub (central server that receives test requests), 2. Nodes (machines that run the actual tests). Each Node can run multiple test instances in parallel. This drastically reduces total test execution time and enables cross-platform testing.
Grid is like an Uber dispatcher. You (test) request a ride (execution). The dispatcher (hub) checks available cars (nodes) and assigns the best one. Multiple people can get rides simultaneously.
We need to run our 200 tests on Chrome (Windows), Firefox (Linux), and Safari (Mac). How do we configure this using Grid?