A sportsbook is a place — either online or in person — that takes bets on sporting events. It’s also called a bookmaker, or a “bookie” (though it’s technically illegal to operate as one in most states). Sportsbooks make money by accepting bets on either side of an event and then paying winners from the losers. The house always has a slight edge over bettors.

In addition to adjusting odds for point spreads, sportsbooks sometimes move totals and other types of bets. For example, if the Patrick Mahomes passing total opened at 249.5 yards, the sportsbook might lower the over/under to encourage action on the under. They might also raise the total to attract more action on the over, which is a way to balance bets and create an even flow of action across both sides of the board.

Another factor is the venue in which a game is played, as some teams perform better at home than away. Oddsmakers work these factors into their point spreads and moneyline odds, and bettors can use them to evaluate potential picks.

Online sportsbooks are typically required to verify that a bettor is located in a state where gambling is legal before taking bets. This is usually done through geo-location services that scan a bettor’s device or IP address to ensure they are within state lines. This helps protect customers and ensure that a sportsbook isn’t violating any regulations. However, this can slow down the process of placing bets and is a hassle for punters.