How do you handle time off / vacation requests in a remote company?

Hey everyone! I'm looking to learn more about the time off / vacation management space as part of a tool that I'm building to do exactly this - ptobot.com I decided to work on this as a way to 'scratch my own itch'. As a manager of a remote team with folks spread across the globe, I'm constantly having to figure out who is out, which public holidays are coming up and will we have enough folks around at any given point in time. I'd love to speak to fellow founders or folks that are managing remote teams to better understand what some of their pain points are here. Feel free to leave your thoughts here or reach out to me directly!