Online slots have been one of the most successful types of casino games since their introduction. They’re quick and easy to play, come in practically every theme imaginable and have a massive range of features. They also offer the biggest jackpots of all casino games and can pay out over millions of dollars – but it’s important to know how they work before you play them.

All online slots use random number generator software to determine the symbols that appear on each spin. The RNG generates thousands of numbers per second, and the math module in the game software translates those numbers into results for the reels. The results of each spin are then compared to theoretical projections and the winnings, if any, are calculated.

There are hundreds of developers creating slot machines, and many of them have created a number of games that have become extremely popular and profitable for players. Some of the largest developers include Microgaming, iGaming, NYX Interactive and NetEnt. You can usually find slots by these companies at most online casinos.

Some of the most popular online slot games feature a special theme or story. These themes can be based on television shows, movies, video games or even real-world locations. The themes can be exciting, dramatic, humorous or romantic. In addition to the story, some slots have extra features such as wild symbols, scatters or progressive jackpots that can increase your chances of winning.