The first slot machines had a horizontal line across the front that represented the payline. If you matched up symbols on the payline, you’d win a prize. Originally, these machines were made to generate money, so they replaced prizes with candy. The strategy was the same as that used in modern slots, though the payout amounts were not commensurate with the odds of winning. Even though the game has evolved to include a variety of features and bonus games, its history dates back to the 1870s.

Random number generator

When a player clicks on a spin button in a slot machine, the outcome is determined. The Random Number Generator (RNG) is used to generate these random numbers. While the exact method used to generate random numbers varies depending on the game, the outcome of an online slot is always random. Random Number Generator testing is available from a number of third-party companies, including GLI, iTech Labs, and Technical Systems Testing.


Reels in slot games vary in design depending on the type of game. Some require groups of matching symbols to line up on consecutive reels while others have a fixed number of reels. The most common type of reels is the spinning reel. Other types of slot games feature different payout methods. While some games have a fixed number of reels, others have many more. For example, you can win more by choosing a higher-paying game.


Paylines in slots are the dividing lines between the symbols that can be won and the prizes that can be won by lining up similar icons. The more paylines that are present in a game, the more options a player has when selecting the symbols. These paylines are often invisible, but they can be spotted by counting the number of lines along the side of the reels or by looking at the paytable. Although symbols still appear on the reels, the paylines act like a grid over the reels.

Bonus features

Depending on the slot machine, you can activate bonus features that can increase your chances of winning. These special features can be triggered by scatter symbols or different bonus rounds. In addition to enhancing your chances of winning, these features can unlock jackpots, unlimited progressive multipliers, or additional free spins. Here are some examples of bonuses that you may want to activate on your favorite slot machine:

Machines with multiple paylines

Multi-line slots have several different kinds of paylines. The payout depends on the value of the symbols that make up a winning combination. Generally, lower paying symbols are the upper deck cards, characters, or fruits. On the other hand, higher paying symbols include diamonds, fruits, or galactic creatures. Each type of payline has its own unique payouts. Read the paytable to find out how each pays. In general, the more paylines a game has, the greater its chance of winning.

Variance of payouts

Volatility and variance are important aspects to consider when playing slot games. Volatility measures the distance between the expected and actual payouts. Some slots include a volatility rating while others don’t. The key to identifying a high-volatility slot is the size of the jackpot and bonus features. If the slot offers both, then it’s likely that you’ll be happy with either. But how do you know which one is right for you? Read on to discover more about variance in slot games.