Online sports betting, also known by sport booking, is the practice of placing bets on sporting events. Historically, on sporting events were placed based on the outcome of the event. Despite this, PASPA has largely prevented betting on sports online and in person, although Nevada has an exception. In the past, gamblers had to visit a sports betting establishment to place bets. Sports booking apps permit people to place bets from their mobile devices and make payments. They also function as a digital clearinghouse that can receive bet calls and pay outs.