Online Slots Full Guide

Slot Machines & Online Slots Guide 2024


You may know them under a different name. Fruit machines, puggy or simply slots, yet all of these terms designate the same games most of you are quite familiar with. It doesn't matter if you haven't been to a land-based live casino before, you most likely have seen them in a bar near you, during your favorite movie, TV show, or on the world wide web.

You can see them now at AU Slots by just clicking a tab or touching your screen. Yes, we have over 2000 real money slots & casino games in 2024 to choose from, each and every one promising you colorful entertainment, countless paylines, plus amazing progressive jackpots.

Mobile Slot Image

We also have some explanations to do especially if you are confused by terms such as paylines and progressive jackpots. Read them all in the next several minutes so you can be ready when the reels start spinning.

History Of Slot Machines

Let's start with a little bit of history first. Do you know when and where slot machines were invented? In the late 1800s, in New York, USA. It was a company named Sittman and Pitt that first developed a similar machine to the modern video poker. The technology was quite simple: a pack of cards minus Ten of spades and Jack of hearts displayed onto five columns very well-distinguished called drums. Whoever wanted to play had to pull a lever and wait for a good poker hand. If you had a pair of kings, you got a beer on the house and if you saw a royal flush in front of your eyes, the owner could reward you with cigars and more free drinks.

Liberty Bell Slot Machine by Charles Frey

At the same time, on the other American coast, in California, mechanic Charles Frey invented a much simpler machine with only three drums and five basic symbols: horseshoes, diamonds, spades, hearts, and a Liberty Bell. The jackpot was ten nickels aka 50 cents and it was rewarded when each drum showed a bell.

Going into the 20th century, slot machines picked up steam and soon enough, they started giving away chewing gum as payouts. The drums had different fruity flavors as symbols, thus the name Fruit machines. Also, to celebrate the early days, many slot machines still have fruits as symbols, but no actual chewing gum as rewards, just some good old cash to fill your pockets.

In 1963, an American company name Bally Manufacturing patented the first slot machine that was fully electromechanical. The slot could operate independently and pay the winner up to 500 coins without any outside help.

The first true video slot was built in 1976 and had a 19-inch TV display plus a logic board to compute all possible permutations. It was first seen at the Hilton Hotel, in Las Vegas.

How To Play Online Slots

After that, the slot industry took off big and with the emergence of the Internet, in the 1990s, it spread even more, worldwide, quickly becoming the game of choice of every online casino player.

Modern Online Slots Screenshot

It is also the game of choice here at AU Slots with a game selection worthy of legends, over 1000 online slots & games ready to spin out of control. To play for real money is easy: just log in or create an account if you don't have one already, make an instant deposit using our wide range of payment methods, choose a random game from our list, place a bet, and spin those reels. It doesn't matter if you are in front of a PC desktop, laptop, smartphone, or tablet, the slot will run flawlessly.

There isn't a generic explanation of how online slots work as each and every one has its own rules, paylines, and paytables. What are these paylines and paytables, you ask?

Basic Terminology Of Real Money Online Slots

Reels (Drums)

The first term you need to get familiar with to understand slot games. In all such games, the display is divided into columns or sections of the same size & format that are very well distinguished among one another. That's a reel or a drum.

5 Reel and 20 Paylines Game

The first-ever slot machine had five reels to complete a traditional qualifying poker hand. The next ones had just three for less complexity, more ways to win & more fun. In fact, three reels have been the standard for a while in the 20th century and many online slots still keep that standard.

Each reel has many symbols which may vary from one game to another. When you play, the reels spin and produce an outcome that may be or not be in your favor, depending on the paylines.



In the past, defining the payline was pretty easy. Take the Liberty Bell machine invented by Charles Frey, for example. The payline, in that case, was the main row. If you had three bells in a row, you would win 10 nickels. Many slot machine including the video slots of the 1980s and 1990s followed the same pattern.

In the Internet era though, to make it much more entertaining & also to give the player more chances to win, paylines are much more diversified so it's not only the horizontal that matters anymore but also the vertical, diagonal, zig-zag, and some other wacky patterns. Which means from the limited combinations from the past, some online slots have thousands of possible paylines. Just see for yourself.



The video slots of old with TV sets as displays all had a list of payouts printed on them, commonly known as paytables. On those paytables, you could see possible winning combinations and the payouts for each combination.

Big Bad Wolf Paytable

This is still the case with many slot machines, some 50-odd years later, from Las Vegas to Macau. You can also see them online at AU Slots for each online slot game. It’s always good idea to check-out the Paytable before playing certain slot. You can get a sense of possible winnings & payouts if Lady Luck is on your side.


FREE Spins

FREE Spins are extra virtual coins or extra bets you can place without any charge. Many real money online slots offer winning combinations as FREE spins. In fact, most of the Bonus Features relay on Free Spins.

Free Spins Feature Won

We also offer you FREE spins every time you make a new deposit on our platform. For even more such goodies, be sure to play on AU Slots regularly and show our loyalty to us. We will make sure you are rewarded in full, just like a true VIP.


Progressive Jackpot

Think of the lottery: when nobody guesses the lucky numbers, not only will the grand prize carry on to the next draw, but it will also increase in value and add new money wagered on top of the old bets. That's the progressive jackpot in a nutshell.

Online Progressive Jackpot

For video slots, every time the jackpot is NOT won, and new spin passed, it will increase progressively until a lucky winner redeems it. After that, the progressive jackpot resets and the count starts once again.

We have a wide variety of progressive jackpot slot games all grouped in the Jackpot tab. Check them all out & start playing today.



All the nice graphics you see on the reels. In the late 1800s in New York, the symbols where actual poker cards. In California, the Liberty Bell had five basic symbols: horseshoes, diamonds, hearts, spades, and bells.

Today, you will find countless other symbols from the traditional fruits to all kind of lore from your favorite movies, TV series, and video games.


Wild Symbols

Wild Symbols are the jokers of the real money online slots. They can replace all other symbols to make the best possible combination for you (except scatters in most cases). Some games add multipliers as wild symbols, while others will allow you to re-spin or change more nearby symbols for even more winning combinations. Check out our slot game selection if you don't believe us.

Behind The Scene: Video Slots Technology

The old slot machines with three physical reels and ten symbols on each reel were somehow boring. Why? Because of the lack of creativity & limited paylines. Even the rarest winning combinations had about 0.1% odds of happening. This is actually why the operator couldn't set high jackpots.

The increase of symbols to an average of 22 didn't help much in terms of both jackpot prizes & paylines.

Virtual Reality (VR) Glasses

With the emergence of computerized video slots though, operators could now manipulate the frequency of a particular symbol which meant much more maneuvering in terms of jackpot prizes, especially with the number of symbols increasing to 50 and more per reel.

The Internet and online casinos took the next obvious step and diversified the paylines from the tradition horizontal to all kinds of patterns and permutations that could be calculated in a matter of milliseconds. This is why we're currently living a golden age of slot games, all fun & entertaining, with hundreds and even thousands of paylines, not to mention HUGE progressive jackpots that could change your life forever.


Random Number Generators (RNGs)

Nowadays, behind all online slots & online casino games for that matter stand the notorious random number generators or RNGs.

RNGs are mathematical algorithms that generate a sequence of random numbers. In fact, the algorithm is called pseudorandom number generator for it is based on a deterministic initial value called the seed.

How does RNG work in online slots? The algorithm is virtually always ON generating numbers at incredible speeds. When you place a real cash bet and hit or touch the Play button, the software determines which was the most recent number generated & based on that number, it presents an outcome to the player. Of course, the player sees “graphical representation” instead of numbers.

Slots Payouts

Yet how do we know the frequency of a given winning outcome? Can you as a player know such odds? Nowadays, as the gaming industry is more transparent than ever, you can find out your chances of winning at online slots by looking at statistics like Return to Player.


Return To Player (RTP)

Return to Player (RTP) or ‘theoretical percentage payout' (tRTP) is a percentage that shows how much of the wagered money is paid back to the players. Usually, real money online slots have an RTP ranging from 92% to as high as 98%. What does this mean exactly?

To clearly understand the term, let's think of a hypothetical slot game in which you can bet only $1 per spin, no jackpot involved. That slot has an RTP of 90% meaning after 1,000,000 + spins, it will reward its players with $900,000, while the rest of $100,000 can be regarded as rake or House fee.

Its worth to mention that millions of spins are needed for the RTP to reach expected value. In a real world, rarely average slot player reaches that figure on a certain slot game. Real “RTP” however, represents the RTP of the player’s session. Naturally, it can vary from low numbers to thousands. In other words, losing or a winning session.


Probability and Accounting Report (PAR)

RTP is not the only statistic available that could help you understand how online slots work. Probability and Accounting Report (PAR) or Paytable And Reel Strips (PARS) could offer you some fresh insights about the world of slots, in general.

This stat is not as used as RTP. You will find many games that not offer this kind of information to the player. But there are many examples of obsolete slot machines with their PAR included. Why does it matter since you can't play them anyway? It can clarify the psychology and not necessarily the logic behind the numbers.

Huge payout on video slot game in 2019

What you need to understand is that outcomes and payout odds aren't quite proportional. For example, the logic would tell us that a 1-to-1 payout would happen more often than a 2-to-1 payout which would happen more often than a 4-to-1 payout. The thing is… it usually doesn't. While the 1-to-1 payout would indeed be the outcome that happens most often, there will be many cases where a 4-to-1 payout will occur more often than 2-to-1, just to spice things up for the player. That means the 2-to-1 outcome will occur much less often than we expect so the numbers match with the RTP, in the long run.

Online Slots At AU Slots

Now that you have learned many useful things about real money online slots and also added some quite hefty statistical tools in your player's toolset, it's time to experience the action yourself, see the reels spin, read the paylines, and get rewarded with a BIG payout. Or maybe the progressive jackpot you always dreamt of.

Online Slots Selection by different Software Providers

Just have a look at all the games and all our top gaming providers. Our slot game selection includes over 1000 titles developed by:

  • Betsoft
  • Isoftbet
  • Booming Games
  • Lucky
  • Endorphina
  • Nolimit
  • Quickspin
  • Tom Horn
  • Evoplay
  • Wazdan
  • Fugaso
  • Xplosive
  • Ganapati
  • Habanero
  • Igtech

Start playing now, on your desktop and laptop, smartphone and tablet. The choice is yours!