Slots Software

Why you should read this page

By reading this page you’ll learn all about the software that drives slot machines. You’ll learn about the many different software types, the pros and cons of each type, how software odds work, the process that is behind keeping slot machines and other online games fair, and you’ll gain a new level of appreciation for the software itself.

When you play an online slot you're not just gambling, you're enjoying one of the most sophisticated pieces of software on the net.

OK, it's a piece of software that can make or break real-money gamblers, but behind the bright lights and reels there's still the same beating heart that runs many popular online games.

Video slots today are programmed in languages that work perfectly for today's players. They can be played via download programs saved to the desktop or rich multimedia platforms which let you gamble in your web browser.

The result is a lot of choice for the gambler, and ever more sophisticated games to pack into casino lobbies. Let's take a look at how slots software gives you the best chance of bagging a big win.

Online slots hit winning combinations in accordance with how their random number generator (RNG) performs. A slot machine’s RNG is constantly running even when the reels are not spinning.

How Do Online Slots Work?

Online slots are governed mainly by two things: a par sheet and a Random Number Generator. The par sheet includes all the game mathematics that governs what odds are paid out by the slot.

Par sheets include what symbols are included on each reel, and in what order. An algorithm is then programmed into the slot which stops the reels at random. It's this RNG, or Random Number Generator, which makes online slots fair on each and every spin.

What Is The RTP?

The payouts programmed into the slot determine what the game's RTP is. The RTP, or 'Return to Player percentage' is a rough payout made to players on average over the long-term. The higher the RTP, the lower the casino house edge, and the more that players can win.

Of course, this figure is just theoretical. Players can go on a lucky streak and come out big winners for just a small stake. On the flipside, they can win a few spins then dump a whole bankroll. By that point they might just call it a day.

RTPs in land-based casinos are strictly enforced by local gaming jurisdictions. You will usually find RTPs of 80-95 percent in Las Vegas casinos. Online, however, RTPs tend to be much higher, around 91-97 percent. Without the overheads of a live casino, online slots sites are able to promise much higher average payouts.

Return to Player (RTP) percentages for online slots tend to run in the nineties, with the best slots offering a payout percentage ranging from 95% to 99.5%. The higher the payout percentage, the lower the house edge, and the better chance a player has of making a profit.

Independent Slots Audits

RNGs in online slots are independently audited by external testing labs. Look for the test certificates on casino homepages. These prove that slots have been checked for fairness.

Although not exclusive to all slots sites, you will find certificates from major testing labs like eCOGRA and TST. Both have been operating for years, and are trusted with ensuring casino games are random and accurate.

Slots Software Types

Mac OS / Windows

Native download apps work by installing games straight from the online casino or slots site. A slots suite is saved to the player's hard drive and can be loaded up at any time.

A little more secure and solid than an instant-play game, native games have the disadvantage of only working for your operating system. If you use a less-used operating system like Linux, you may have to opt for instant-play slots which load via the web browser.


- Perfect for mobile phones of all operating systems
- Adaptable over desktop and mobile
- No need for a separate player
- Works on devices that can't run Adobe Flash

- None that we can find

Most slots these days are programmed using HTML5. Unlike Flash HTML5 is easy to adapt across multiple platforms like PC/Mac desktops and mobile devices.

What makes HTML5 so good is that it was designed specifically with multimedia content in mind. There's no need for a separate player like Flash, either.

And whether you're using an iPhone, Android tablet or Windows smartphone, HTML5 can be handled easily. In particular, Apple iOS users can enjoy HTML5 games when Flash won't work. HTML5 has also been shown to run about 50 percent faster than Flash, making faster slots play possible.

Adobe Flash

- Smooth animation and gameplay
- Works with most operating systems

- Mac OS still has issues with Flash
- It can be hacked
- It runs slowly on platforms like Linux
- Now blocked by Firefox browsers
- Players need to keep their Flash Player up to speed with regular updates
- It can run slowly on some devices

Some developers make slots in Adobe Flash. While not ideal for some systems, it allows for fast animation and graphics on the reels.

Adobe Flash Player allows certain games to be played via the web browser. This means if you have an operating system like Linux or Mac that may not have a dedicated slot version, you can play games instantly.

It's worth keeping your browser and Adobe Flash Player up to date. Install Adobe Flash Player 11.3.300 or higher to make sure all games load without problems.

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