This is done to let to analyze your own game performance by revisiting your game stats. But you are not allowed to use such software while you are playing on PokerStars. To sum it all up, the answer to the question Does PokerStars allow HUD?  is, yes.

Here's why you should use Poker Copilot as your PokerStars HUD: Poker Copilot has worked with PokerStars since 2008. We're on their list of officially approved software. Poker Copilot supports scheduled tournaments, ring games, "Sit & Go" tournaments, "Spin & Go" tournaments, and Zoom Poker (Zoom for Mac only).