Since their inception towards the end of the 19th century, slot machines have grown from fancy randomized vending machines to video games worth playing on their own right. Where the technology in physical slots might be pretty intuitive, online slots are much more of an enigma to most of us. Below, we’ll unveil the technology behind slots that online casinos use – and how it differs from land-based slots.
To make things even clearer, we’ll go through the technical aspects of online slots guided by the case study of an online classic: Random Runner. This slot might look like a straight copy from its land-based predecessor, but it uses the same technology that other online slots use. This difference offers players a RTP of more than 95% (instead of the classical 85%), while keeping the game fairer, more balanced, and unbiased.
Random Number Generator (RNG)
The technology at the core of online slots (and other casino games) is the Random Number Generator (RNG). This piece of software has a rather self-explanatory name, but offers a major difference in how slots are played compared to the ancient versions. Nowadays, every slot machine you’ll find has a RNG, no matter if it’s one of the newest online video slots or a classic machine standing in a forgotten corner of a Las Vegas casino.
The Random Number Generator is a built-in algorithm that decides the outcome of every spin in the slot. To keep this fair and unpredictable, the RNG produces a staggering amount of possible outcomes per second, based on the algorithm and the characteristics of the slot you’re playing. By pressing the play button on a slot, you automatically select the outcome in that very moment, which is subsequently presented to you.
This means that every spin is completely independent from the spin before it, or the next one up. Every spin has an outcome that’s unique to that spin, based on the rules that are built into the algorithm, such as hit rate, RTP, and volatility. In any given second (even when you’re not playing), there are thousands of possibilities that all adhere to these rules.
To make sure the RNG is truly a Random Number Generator, designated third party auditors rigorously test the RNG that’s at the basis of online slots. Often, you’ll see slots verified after having played a billion spins – ensuring that the RNG does what it’s supposed to.
Example: Random Runner
To give more insights into how the RNG makes slots work, we’ll pick apart one specific slot in our case study. The Random Runner. This slot by developer Stakelogic is a digitized version of a land-based classic. As it works with three reels and five win lines, it’s a great slot to see the RNG in action, but the same principles can be applied to other slots, sometimes with over 100,000 win lines.
The Random Runner slot has a twin setup. Players can choose to play on three reels or six reels, where two simultaneous games are played next to each other. For the sake of argument, we’ll explain one reel set, but the same principles apply to both sets at the same time.
In Random Runner, there are eight winning combinations and a scatter symbol. Each of the winning combinations will have an individual hit rate. A combination of three watermelons worth 16 times the total bet might hit every 70 spins on average, whereas a cheaper combination of plums (8 times the total bet) might hit every 20 spins on average. Each combination has its own hit rate and the machine overall has a RTP of 95%.
With every spin, the reels are configured again, using the above variables for the algorithm. Instead of having a set number of outcomes that are printed on the roles, the RNG rapidly goes through all the possible outcomes based on the predefined set of rules. When you remember that a deck of 52 cards has a number of possibilities that takes 67 zeroes to write out, the configurations of Random Runner (using eight symbols with different probabilities) are just as plentiful – and completely fair and random, too.
The future of online slots
Although Random Runner is a great case study to explain the ins and outs of a RNG, most slots have already developed beyond this. A great example is the popular Megaways engine, that supports up to 117,649 win lines (or more), by giving dynamic reels that change the number of visible symbols with each spin. This shows the power of mathematics in slots, and gives a glimpse of the possibilities in the future of slots.
Other developments are the influence of casual gaming in slots: many slots have adopted a hybrid gaming model, where you can unlock extra features or get special bonuses after a fixed number of spins or gathering a certain amount of special coins. A closely related development, the skill-based slot, gives players the chance to gain more control in (closely cordoned-off sections of) the slots.
Lastly, by offering the option of buying a bonus round, slot developers have further injected the slots model with steroids. In an extreme (and controversial) example, No Limit City launched San Quentin, a raunchy slot that gives players the option to buy a bonus for 2,000x their normal bet, which gives them the chance to win a maximum of 150,000x their bet.