Online slots are one of the most popular casino games on the internet. Players place their wagers and spin the reels to win money by lining up symbols on horizontal paylines that run vertically (although some games have diagonal or vertical lines, too). Winnings are based on a random number generator, which is routinely audited by regulators to ensure fairness. Little to no skill is required to play online slots.

Each slot machine has a different mathematical characteristic that determines how often it pays out and how large those wins are. This is known as volatility or variance in the industry. Many online casinos make the variance of their slots games difficult to understand, partly because they want to hide how much house edge these machines have over their players. However, you can figure this out yourself by studying the maths behind slots.

The best online slot sites offer a huge variety of games from multiple studios. These include the big names like NetEnt and IGT as well as smaller boutique providers. They include all sorts of Megaways and instant wins slots, as well as the classic 5-reel and 3-reel machines. These sites curate their range of games to cater for all tastes, including a wide range of themes and features like sticky wilds, symbol transformations, multipliers, expanding wilds and free spins. Some also offer progressive jackpots. Many of these games are available to play on mobile devices as well.