BeReal

BeReal builds its whole interface around a single daily notification. At a random time it pings everyone at once, you get a two-minute window, and the app fires both cameras simultaneously to capture front and back in one frame. That constraint is the product. There is no curated grid, no algorithmic feed, and no posting on demand; the timeline is just today's posts from your friends, and crucially you can't see theirs until you've posted your own. The reveal is gated on reciprocity. Retakes are logged and shown, late posts are stamped as late, and that honesty-by-design friction is the entire premise. The flip side is fragility: miss the window and the moment is gone, and the interface offers almost nothing to do between notifications, so engagement lives or dies on that one daily prompt.