Online Slots Information

Welcome to Red Spins comprehensive guide to online slots. You may be a complete novice looking to take the plunge into slots play for the first time. Or you may be a casino regular who just wants to get the best out of their spinning. Either way, we’ll address and answer all the important questions to help you on your way, including:

  • What are the different types of slots?
  • How to play Online Slots
  • Are they truly random?
  • What is RTP?
  • How does slot variance work?
  • Who are the best slot developers?

Our article will help you understand how slots work, which are the best, and why there’s an art to choosing the right slots for you.

Brief History of Online Slots

Online slot machines appeared in 1994, when the first ever online casinos launched. These were based on software by the Isle of Man developer, Microgaming, who is still a key player in the industry to this day. Of course, the history of slots themselves date back much further. Charles Fey invented the first slot machine as we know it today at the turn of the 20th century. The device, known as the Liberty Bell Slot Machine, was the first mechanised gambling device of its kind.

Slots machines became an important part of the casino experience throughout the 20th Century. They’re easy to play and thrilling to win with lights, sounds, bells and whistles. Of course, as the technology improved, so did the possibilities. In the 1980s and 1990s the first video slots were developed which paved the way for today’s online slots.

Different Types of Online Slots

For all intents and purposes, there are 3 main types of online slots. These are classic, video and progressive.

Classic Slots

Essentially, these are based on the earliest forms of slots and fruit machines that you may see in a pub or arcade. They often have just three reels and the recognisable fruit, bell, bar, and seven symbol design. Though these slots are available digitally, they eschew all the extras and frills of a video slot. Examples of online classic slots that we feature are:

  • 7s to Burn by Scientific Gaming
  • Jackpot Jester 50,000 by NYX
  • Cash Splash 5 Reel by Microgaming

Video Slots

The great majority of the slots you’ll find on our online casino are video slots. Fusing the concept of the classic slot with the video game revolution, a hybrid of the two was created. These slots have greater possibilities in the game, including more reels (at least 5), more ways to win, more symbols, bonus games, and generally just more options. They may have videos, music and graphics which elevate the playing experience to the next echelon. There may be free spins rounds, gamble features, and the possibility to ascend new levels, as if you were playing a video game. Some still maintain the simplicity of a classic slot, like Starburst. Others embrace enormous visuals and sweeping narratives like Vikings Go Berzerk, Alchymedes, Dark Vortex and other slots by Yggdrasil.

Progressive Slots

The other main type is the progressive slot. They are usually video slots that have the added feature of randomly triggered jackpots. Some slot developers run networks which build up a jackpot pool from a small percentage of people’s bets. This could be across slots and across casinos; this is why they can sometimes build up to millions of pounds. Then, one random spin can trigger a jackpot win, earning a lucky player a life changing amount of money.

How do I play Online Slots?

Online slots are the most popular part of an online casino because they are simple to play. Often a casino makes over 80% of their revenue from slots. However, there is some terminology to learn, and some tips to help you get the most out of your slots play.

How do I play? First Steps

You’ll see in a slot’s information how much each symbol is worth, and which combinations trigger a win. In the base game, you usually want the most valuable symbol to appear adjacently across every reel from left to right, in order to pay out the most money. Some slots may pay from both ways. You can also check in a slot’s information how many pay lines there are and what the winning combinations are. Some video slots have tens of ways to pay, some have thousands.

Often the most exciting part of the game comes from spinning wild and scatter symbols. A wild symbol will usually substitute for any other symbol, helping you to complete a winning pay line. This is except for scatter symbols. These tend to trigger bonus games or free spin rounds if you happen to get enough of them during a base game spin. Bonus features such as these can be either random games of chance to win more money, or extra spins that either mimic the base game, or transport you to a slightly different, usually more hyper and flashy set of reels. The music and colours will also tend to be heightened, in order to differentiate it from the base game. In addition, these free spins may have multipliers attached. You’ll find multipliers that range from x2 all the way up to x50 per free spin. These give you the chance of some pretty big wins and are often the most thrilling part of a video slot.

How do I bet?

Different slots have different minimum and maximum bets per slot spin. For some, you can bet a 1p minimum on just one bet line. Sometimes there will be a max bet button which allows you to stake the maximum. The variables that you can often control include how many lines you bet on, the level of your bet, and the coin value of your bet. Once you have adjusted these to your preferred level, you should be able to see the total bet value at the bottom of your screen.

Many slots offer the opportunity to perform automatic re-spins. You can choose the bet level as well as the number of spins, and the computer will spin for you. Often there will be a setting where if you reach a bonus game, then the spins will pause so that you can experience the full thrill.

To summarise, before you start a new slot, have a look at this handy checklist:

  • Check the pay lines & symbol values; have a basic idea of what is a winning combination.
  • Does the game have bonus or free spins rounds?
  • Check the Return to Player (More on that below).
  • Craft your perfect sized bet and check the total bet.
  • Check your balance!

Are Online Slots Random?

Some players are worried that casinos can rig online slots in order to fleece them. A casino, by law, cannot alter the outcome of slot spins. This is regulated by different official bodies around the world. In the United Kingdom, the Gambling Commission regulates the industry and ensures that casinos and slots operate fairly and with transparency.

An online slot is programmed to be random through what is known as a PRNG (Pseudo Random Number Generator). This computerised programme ensures that over a long period of time, a slot will pay out in accordance with its RTP (Return to Player). The Gambling Commission requires game developers and casinos to test their slots’ RTP frequently, to make sure they are spinning randomly. There are many testing bodies in the industry, such as NMi and eCOGRA, which stands for eCommerce Online Gaming Regulation and Assurance.

What is Slot RTP?

RTP is the Return to Player. Each slot has an assigned RTP which is given as a percentage. It is effectively the inverse of the “house edge.” For example, Starburst has an RTP of 96.1%. That means that statistically, over a long period of time, for every £1 wagered, the player is getting 96.1p in return.

Of course there is variation on this from spin to spin. You may spin once and win hundreds of pounds. You may spin eight times and lose all your money. However, over an infinite period of time, the result will get closer to this RTP. Therefore, it is wise to choose the slots with the highest RTPs as you have statistically the highest probability of return.

Progressive slots tend to have lower RTPs. This extra income is then pooled by the progressive network to form a jackpot. This is how these jackpots can run into the millions.

Different Online Slot Variance

As we explored with RTP, slots will behave in different ways depending on how they are programmed. Two slots may both have an RTP of 95%. However you may notice that one slot pays out frequently but low amounts of money, and the other slot pays out very infrequently. Yet when it does, the sums of money are much larger. This is to do with variance. Unfortunately, slots developers don’t often give a figure for variance in their slot’s information. However, you can soon get an idea through the spin patterns. Slot variance is also known as Volatility. These are the three common categories.

  • High Variance
    A high variance or volatility slot will pay out infrequently. But when it does, the rewards will be larger. This can either be in the base game, where you line up high paying symbols. Or this could be when scatter or feature symbols trigger a free spins or bonus game which can prove to be very lucrative.
  • Low Variance
    A low variance or volatility slot will pay out often; sometimes more often than not. However, these will be smaller amounts that usually don’t amount to much more than the bet. Starburst, the popular slot by NetEnt, is a classic example of a low variance slot. There are no bonus features or extra spins rounds. However, the frequent appearance of Starburst Wilds in the base game gives players hours of gently pulsating, synthesizer-driven thrills.
  • Medium Variance
    This, naturally, is somewhere in between. The majority of online slots fall into the medium volatility range, not hugely defined by the extremes on either end.

Online Slots & Welcome Bonuses

An online casino will frequently offer a deposit bonus or free spins on a single slot, selection of slots, or an almost entire collection of slots. Free and Bonus Spins are an excellent way to test out a slot or set of slots without the jeopardy of spending your own money. Some sites, like us, will even offer a no deposit spins bonus. All you have to do is sign up, validate your phone number via text message, and you’ll get some free spins to play with.

The Best Slot Developers

We’ve mentioned some of the very best slots in this article, which are made by the best companies. These are the top slots developers to look out for.

  • NetEnt – These Swedish legends are industry leaders when it comes to online video slots. The top game to look out for is Starburst.
  • Microgaming – As we mentioned, these guys are pioneers. Check out Immortal Romance, a high RTP slot about vampires.
  • EyeCon – They make some of the most popular slots around. Their number one title, Fluffy Favourites and its variations, is one of the most recognisable online slots.
  • Reel Time Gaming – They started by creating video slot terminals in brick and mortar casinos. Now, their instantly recognisable slots have translated online. Check out: Fishin’ Frenzy.
  • IGT – IGT stands for International Game Technology. They have produced some of the most iconic video slots of all time. Check out: Cleopatra.
  • WMS – Now a part of SG Gaming, WMS (or Williams Interactive) are behind perennial favourite Raging Rhino.


We hope that our Online Slots guide will give you all the tools you need to get started. Follow these steps and keep track of our checklist. This will help you get the most out of your slots play and help you avoid confusion and doubt. A knowledgeable spinner is a happy spinner.