A sportsbook is a gambling establishment that accepts wagers on various sporting events. A sportsbook can be a physical store, an online site, or even a mobile app. Some of them focus on one sport, while others are more diverse and offer a wide variety of bets. They also often accept bets on pivotal world events, such as the Oscars and Nobel Prizes, as well as elections. They may also offer what are known as novelty bets, which range from the commonplace (e.g. royal baby names) to the bizarre (e.g. when will aliens invade).

The concept of sports betting is nothing new, but legalization has changed the game. Sportsbooks must comply with state regulations and can be subject to geo-location verification, which means a player’s location will determine whether they can place a bet. Moreover, deposit and withdrawal limits can vary widely depending on the payment method and service fees.

In the United States, only Nevada has long offered legally sanctioned sportsbooks, but in recent years Oregon, Montana, and Delaware have offered limited forms of sports betting. A 2018 Supreme Court decision allowed more states to legalize sportsbooks, and most of them allow wagers to be placed online.

With so many of these operations now taking bets online, they are also better able to track user behavior and identify early indicators of problem gambling. Several sites have begun to tie responsible gambling more closely with CRM, which allows them to change the marketing messages and push notifications that customers see if they have demonstrated early signs of problematic play.