Online Slots and Their Main Features

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Deni

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Published: April 24, 2018
Updated: August 15, 2025

Back in the old days, without online casinos, slot machines were only found at land-based gaming establishments and certain pubs.

You could pop your coins into the machine and pull the lever arm at the side to roll the three reels for the chance of matching traditional ‘fruit icons’ or big ‘red sevens’ along a single payline and win a cash payout. Now, there's a lot more to it!

A brief history of slots

Those ‘one-armed bandit’ type machines have now mostly been replaced by more sophisticated versions that run on electronics with processors and digitally mastered reels on the screen.

Online slots and their main features — What are the main features of online slots?

The modernised programs have allowed for gaming to become far more versatile, offering the player more than just the run of the mill reel roll. They even come with special features and some more complicated bonus rounds.

What are online slots?

Online slots are an answer to the trends of this age, where developers are reproducing many of your favourite slot machines, but with the addition of many more titles or features. These can be played from any kind of device from practically anywhere in the world.

With the advance of the information age, the whole world has focused entirely on the internet. It only stood to reason that sooner or later the gambling industry would take advantage for profit and gain.

After all, the internet can most certainly reach more users than any single land-based casino ever could. You can now play from the comfort of your home, during your lunch break or while waiting for the train.

Online gambling aims at entertainment when you choose it. And best of all, it offers you the chance of winning while on the run.

Which are the best online slots?

There are literally thousands of options available and the answer depends on what you like to play: be it classic slots or progressive jackpot titles. The good news is you have a lot (coming from the best providers such as NetEnt, Microgaming (now Apricot), Pragmatic Play, etc.) to choose from.

Themes available in the online arena include:

Classic slots – These are the most basic machines, often encompassing only three reels and offering very few special features. It’s the way slots were formed in the beginning.
3D slots – Some have moved away from traditional 2D graphics to provide something more astonishing and upmarket.
Vegas slots – These resemble their land-based counterparts found in Las Vegas and other such places.
TV & movie slots – These titles are made in homage to famous TV shows or films.
Holiday slots – These are made to honour the variety of holiday seasons celebrated around the world, such as Christmas, New Year, Valentine’s Day, Halloween, etc.
Progressive jackpot slots - The jackpot on these slots grows as betting increases throughout the entire network. In the end, a lucky player wins it all.

Check out the variety of slots directly here:

Classic Slots Learn more

3D Slots Learn more

Vegas Slots Learn more

TV & Film Slots Learn more

Jackpot Slots Learn more

The above categories are just the start, but as you can see, there is a slot theme for every taste. Within those themes are genres, you can find horror, action, adventure, animation, fruity fun, sci-fi and more. No one has an excuse for being bored.

How do slots work?

The formula is one you're well familiar with: load credits via your online wallet, bet on the next ‘reel roll’ and win if you get the right combination. Certain symbol values differ from others, so the payout will differ based on the icon you have matched.

Keep in mind that often the least number of matches on any one payline is three, with the most usual being five. On a five-reel online slot, if you match five of the highest paying symbols on a given payline, you will win the ‘jackpot’ or top prize. The payout then can vary from 10x to multiple thousands times your stake.

However, online slots come with a lot more extras and fun features to keep you entertained while you do that. Let's start with the basics:

Reels

A reel is one of the vertical columns that carry the game icons/symbols on them. When you press spin, it is these that roll at speed and stop randomly to produce the ‘hand’ for that particular wager.

Reels can vary from 3 across and 3 high to 12 across and 12 high (colossal reels), but the average reel set is usually 5 icons horizontally by 3 or 4 icons high.

Paylines

A slot payline is a predetermined pattern set on the reels. If you land matching combinations across that line (usually from right to left), the game will pay you for a win. These paylines can run horizontally and diagonally in both straight lines and zig-zag fashions.

Titles can range from set patterns of 1 payline to 100 paylines.
There are some that adopt the multiway payline feature, which can offer you between 243 and 117,000 ways to win. Here, instead of set patterns, wins can be made if matches merely occur with the same symbols adjacent to one another.

There is also a difference between fixed paylines and varying paylines.

Fixed means you are forced to bet on all paylines available.
With varying paylines, the amount you choose to wager will determine how many paylines you bring into play.

Bet/wager

To be able to spin the reels of a slot machine, you will need to ensure that a bet is first placed. This can be controlled on the game interface.

Be sure whether you are playing a fixed payline game, as this will affect your total wager. You will need to be cognisant of the fact that the more you bet, the more you can win, but on the other hand, the more you can lose too.

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It may be wise for you to read up on our guide on online slot strategies.

Bonus rounds of online slots

With the increase in competition in the online gaming segment, the only way the developers are able to stay ahead of their rivals is by becoming more inventive in the ‘game features’ department.

This is why you will find that the more modern games come with a variety of special features and bonus rounds in order to spice the ‘flavour’ of the game up a bit.

Free spins – These can be triggered during base gameplay in many different ways. Basically, this round will allot a specified number of spins of the reels without deducting any cash from your bankroll. It’s a free chance at wins. Often, there will be added special features in this round, such as extra Wild symbols or win multipliers to help you along to decent wins.
Pick bonuses – This type of bonus game will often grant you a number of symbols to choose from and a specified number of picks to click on these. Prizes could vary from instant cash and multipliers to triggers for other bonus games.
Bonus trail – Here, too, you can click on random items along a trail to reveal prizes or booby traps. Make it to the end of the trail, and you will generally receive a very useful bonus prize.
Gamble feature – Some providers will add this game as an extra chance to boost smaller wins. After a win, you can click on the ‘Gamble feature’ button to stand a chance of doubling or even quadrupling it.

Other special features

There are often other add-on features that keep gameplay alive, that do not necessarily include bonus rounds, but help give added value to them. Here is a list of a few of the most sought-after features:

The nature of a Wild is that it will substitute for most standard game symbols to help produce winning combinations. There are different kind of Wilds to help you win:

Stacked Wilds, which come onto the reels in sets of two or more to boost wins.
Sticky Wilds, which stay in play without disappearing after a number of wins.
Expanding Wilds, which expand to cover a reel’s worth of symbols.
Multiplier Wilds, which will multiply your winnings by a specific amount if they aid in forming a winning combination.
Often, these ‘Wild’ types can combine to form more exciting kinds, such as Expanded Sticky Wilds, etc.

Scatters are special icons that do not need to be on a payline to produce a win. Often, these symbols will be used as triggers to open bonus rounds (generally, that's three or more Scatters on the screen).

Online slots hold the greatest variety of titles for your online gambling entertainment, along with some of the best features in the iGaming arena. Head to one of our top online casinos to experience a slot adventure to suit you and see all of this for yourself!