Selenium grid - Why it's needed

[bhaskar]

Appium - Parallel Execution (Grid)

Is it Necessary to Start Selenium Standalone Server for Parallel Execution? I am able to run tests parallel on multiple devices, by giving different udids , appium port numbers with out configuration json files... **Please let me know Is Selenium Hub should be launched for Parallel Execution? and what is the use when it comes to Appium.!!!** Thank you in advance, Vijay Bhaskar.

Hope this reference will clarify some of your questions.