Slot Game SelecionThe online slots sector is bigger than it’s ever been in terms of the number of games on offer; as the demand grows, so do the number of games. The amount of money that was wagered on them from 2005 to 2015 tripled and that trend has continued ever since.

The quality of these games has taken a huge leap too. You only need to compare some of the early releases, such as Reel Em by WMS Industries, to some of the amazing branded games like South Park to appreciate how far they have come.

One thing that not everyone is aware of is that the casinos don’t actually make their own games. So, even though you land on a casino and see hundreds of titles, these have all effectively been leased from dedicated game developers.

There are a number of reasons for this, but the main one is that the time and resources needed to create new casino games are substantial. By outsourcing this jobs, it means that the casino is able to run the player side of things and then they simply pick and choose the best games from a multitude of game developers.

It’s these developers that have honed their skills over the years, and the technology that is now available enables them to create the enticing feature rich slots that you see today.

How are Slots Made?

The process to create each slot is long and arduous. Each game is actually made from scratch, and even though they can carry basic frameworks over to get a base for the game, each has to be redesigned to make it unique.

Design Team meetingThe average online slot takes about a year to make. This process includes things like the planning, designing, art work, creating the mathematical algorithms, any legal requirements, extensive testing, marketing, and then the publishing of said game. The number of people involved in this will vary.

For example, someone like Microgaming – who are probably the biggest game developer in operation right now – can have a team of around 10 staff dedicated to each game. This number might increase or decrease at certain points in the creation process, but it gives you a rough idea. A smaller company, such as Push Gaming, won’t have the manpower to assign this many people to each game, so their teams might be smaller. Alternatively, they might work in a similar fashion but one which dictates the volume of games they can deliver each year.

The games are actually super-complex as well, and whilst they might look pretty simple in terms of how they work, they take a huge amount of man hours to create. The team involved can include a designer, mathematician (works on the Return to Player percentage), several developers, testers, project manager, and a configurator.

Teams will start the process by brainstorming concepts and what themes might work. If you look at any online casino you often see many slots that are in the same genre, such as Ancient Egypt or Lucky Irish. The reason there are so many is that they are popular themes, so a lot of game developers work to make better games in the same themes, rather than creating totally new niches.

There’s a lot of work that goes into this initial stage and the developers need to utilise things like market research, demographics, and statistics for current games to try and work out what will be popular as a new design, and to whom.

Game Design QuickspinOnce this has been completed, the next phase is to move it over to the design team. It’s then their job to try and create something unique. There are few genre’s that haven’t been explored at some point in the slot industry, so the team can look at how well these games have performed and then create/adapt some sort of theme or design concept from that. It’s worth noting that the games they study can be taken from their competitors catalogue’s as well as their own.

There are a huge number of moving parts to each slot game that need designing and then creating. You need to think of aspects such as paylines, coin numbers, max bet amounts, reels, symbols, volume of symbols, features (wilds, sticky wilds, scatters, fixed reels etc.) bonus rounds, branding, and the list goes on. For every game each of these individualities needs to be considered and then tied down with it a strong plan put in place before anything is created.

Branded Games

Branded slots are the most popular for most casinos, and if a slot developer is able to get the rights to brand a certain game it’s likely that these are going to be best games to play.

BatMan Begins

The reason that the bar is raised for these games is that the brand need to make sure that their business is represented well, and the developer needs to keep the brand happy. At the end of the day, if you are playing a slot like Superman and it is rubbish, most people would put that on the brand and not the game developer, which many will never have heard of. This damages the brand, and that’s a no no.

The initial planning for branded games is extensive and includes discussions with the brand’s representatives which can add to the workload, but it can be easier for developers as the base, and to some extent the art work, is already there. They know the music they can use, the look, design, characters, colours, and even concepts for bonus rounds based on that brand. So, whilst the existing information makes the planning a lot easier, the execution is often tougher to really nail down.

Release and Success Rate

Test PanelOnce all this has been put into place and the slot has been through its design and testing, the real test begins – it is put in front of paying customers in an online casino environment.

Developers will use test panels of between 50 – 500 people prior to launch to get some kind of idea of what to expect. Given that the game is played online, it is fairly easy to get a large amount of feedback before going live.

That being said, the numbers are what really counts and these will be evaluated to see how well the game is performing. Whilst it’s not easy to see exact feedback like you would get from a focus group, you can still gauge how it compares to other slots in terms of money wagered, amount of time played, and frequency of play.

One thing that you will find is that rarely do unpopular slots get a major overhaul. If a game is released and it doesn’t perform very well, the developers won’t pull the game, revise it, then re-release it. Instead, they might make a couple of small tweaks, but usually they just leave it and move onto the next project, taking the data from that game and any money that trickles in.

This is why there are thousands of slots online these days. Are all of them good? No. But a casino can leave them in there on the off chance that a certain niche or genre suits someone’s eye and also the fact that they can boast about the size of their game library.

Variance and Volatility

Source Code Computer Tech

Before we move on, we just wanted to talk a little about variance in slots and how this is factored in by the developers.

As you may or may not know, each game comes with a Return to Player (RTP) percentage. This is basically the amount that the slot will pay out over a theoretical session. The numbers are usually around 90-97% for most online games (note that land-based slots are much lower). So, with a 95% RTP, you would expect to get 95p for every £1 that you staked. A 90% RTP would be 90p for every £1 staked. Obviously, this isn’t literal as the game is random; you could hit a winning streak that blows the theoretical RTP out of the water – that’s what we all hope for, afterall.

The rates that are offered for each game change quite dramatically. This is on purpose though as it makes games function in different ways and keeps them unique.

This all links in with the volatility of the game. This is rated as low, medium and high.

  • Low volatility = Games that pay out often, although usually smaller amounts.
  • Medium = A balance of staggered low and high payouts.
  • High = Games that don’t pay out very often, but when they do, they pay big.

The reason they offer so many variables is that it allows them to cater for a wider range of players. You might have a player that likes to bet small for long periods of time and get a lot of value for their money. This player would fit a low volatility game. You also get players that want hard and fast gaming and have a bankroll to back that up. These players want the chance to win large sums of money and aren’t bothered about the small wins.

Computer MathsWe spoke earlier about a mathematician being an important member of the development team, and this is where they come into their own. They are able to program the games to work in different ways and then fit certain game dynamics. This allows each game to be very different under the hood (or in the programming), which is why you get a plethora of games on Ancient Egypt, for example. They may looks similar but the game mechanics will be very different.

This part of the game development is arguably the most important. The theme, design, features and things like that are all pretty much cosmetic; the biggest twist on how the games work and what makes them popular or not is the variance and the volatility of that game.

Licensing and Verification

eCOGRA LogoAnother vitally important part of the process is making sure that the game is fair. A lot of things need testing for fairness, such as the random number generator to make sure it’s truly random, and nowadays the theme needs to pass certain criteria too to make sure that it’s not targeted towards children or vulnerable adults.

To do this, the games must be submitted to institutes like eCOGRA and iTEch Labs. The testing process will take place before the game is developed, but also throughout its time with any casino to make sure that no secret alterations have been made without being flagged to casino users.

The likes of the UK Gambling Commission oversee this whole process and this goes a long way to deciding whether or not the developers will be granted a license within the industry.

Who are the Biggest Game Developers?

The industry is buzzing with game developers and we’d definitely say that it’s never been so competitive, which is great for the players as the developers are constantly looking to outdo each other by creating bigger and better games. Here’s a list of some of the best in the business right now:


Microgaming LogoImpossible to write a list of the best casino game developers and not include Microgaming. The company were the first in the business and they are definitely one of the best.

Their back catalogue of games is stunning with over 850 titles to choose from across the board. They are best known for their introduction of the progressive jackpot, and have been able to pay out over £800million worth of jackpot prizes, which is just staggering.


NetEnt LogoOne of Microgaming biggest competitors is that of NetEnt. They are often referred to as the best in the business and certainly one of the most innovative.

The company are the brains behind a ton of features that have been introduced to the industry, including Touch technology for their mobile games, creating a seamless integration. Their 3D slots team are doing great things and are surely one of the most exciting areas of NetEnt’s operation.


Quickspin LogoA fairly new company in that they’ve only been online since 2011, Quickspin have definitely been one of the ones to watch in the game development sector.

They came out all guns blazing stating from the off that they wanted to have at least 6 games in design circulation at any one time. They are keen to reinvent the wheel as well, meaning that they almost always come up with new frameworks and features, such as their Hi Roller feature and their brilliant extra spins games.


Yggdrasil LogoYggdrasil wins the award for the most obscure name in the industry, but if their name is odd, their games have been anything but.

This is another company who have been keen to steer their own course and have come up with great features such as iSENSE, BOOST, and Brag, to name just a few.

The games they’ve been able to create have been simply stunning as well. They’re a company that’s still fairly fresh faced as they’ve only been online since 2013, but they would be our pick of the bunch to make waves over the next decade or so – provided one of the big boys don’t swoop in and snap them up.


Playtech LogoPlayTech are another of the founding members of the online casino industry and their virtual doors have been open since the late 90’s. The company are as well known for their work in poker, bingo and sports, as they are casino, but they are still a huge player in this sector.

The company were one of the first to create franchise slots, with links to DC Comics and Batman to name just a few. They also snapped up contracts with popular TV shows such as Little Britain, Who Wants To Be A Millionaire, and Britain’s Got Talent.


Thunderkick LogoThunderkick are a super-exciting game developer, founded in 2012. The team are actually made up of former NetEnt employees who broke away from the brand to create their own games with more creative freedom and control.

They don’t have a huge range of games yet, but they definitely fall into the bracket of quality over quantity. Their trademark, if you will, is quirky characters, and each unique game seems to have them.

Their game, Flame Busters, won the Best Mobile Game at the Videoslots awards in 2017 to highlight how accomplished they have become.


IGT LogoIGT are a pretty interesting company as they were formed back in 1975 before the internet began. They are one of the few game developers who create both online and land-based slots.

The games possibly aren’t as good as the others on the list, but they were able to tie down some branded titles in the early 2000’s which enabled them to offer a solid base of original games. The fact that they’ve been able to adapt to the online world from the land-based casinos is a really cool claim to fame for the company.