YouTube is 99.99% backend. The video player is peanuts to the infrastructure needed to process and serve the vomit-inducing amount of data. A quick search say

YouTube is 99.99% backend. The video player is peanuts to the infrastructure needed to process and serve the vomit-inducing amount of data. A quick search says 183 hours of video uploaded per minute and 694,000 hours of video watched per minute, served globally and rendered to dozens of resolutions and formats, and remember that unlike, say Netflix, this covers a much wider content library. (It's much easier to keep a few hundred gigs of data on global edge CDNs than god knows how many exabytes YouTube has.)