A sportsbook is a gambling establishment that accepts wagers on various sporting events. These bets can be placed online or in person at the venue itself. As more states legalize sports betting, the number of these places has increased significantly. Those who don’t live close enough to a sportsbook can use mobile apps to place their bets from anywhere. They can also place bets on multiple games at once.

When a bettor makes a bet on a game, the sportsbook gives them a paper ticket that they can exchange for money should the bet win. They have to tell the sportsbook what their rotation number or ID is, what type of bet they are making, and how much they are wagering. This information is then recorded in the sportsbook’s system and they can check back on their history to see what bets won or lost.

Most sportsbooks offer a wide range of betting lines and odds, including moneylines, point spreads, and over/unders. The oddsmakers are free to set their own lines, but they usually follow a standard formula that takes into account the expected action on each side. A negative line indicates a favorite, while a positive one means an underdog.

Sportsbooks keep detailed records of every player’s wagering history, tracked when they log in through a phone app or swipe their card at the sportsbook window. They use this data to identify patterns and predict how sharp their customers are. This helps them make informed decisions about when to limit or ban players, and which lines to adjust.