The YouTube Beta program via is an official platform that allows iOS and iPadOS users to test upcoming app features for free before they are released to the general public. While the app is free to download and use, joining the program requires a specific invitation from Google. What is the YouTube TestFlight Beta?
TestFlight is Apple's official service for developers to distribute pre-release versions of their apps to external testers. The through TestFlight offers a glimpse into experimental UI changes, new playback controls, and performance improvements. iOS Tutorial: Beta testing with TestFlight