The History of Online Slots & Their Evolution into Mainstream Gaming

Elias Hubbard
December 17, 2020

One of the easiest games to play online is video slots. For such a simple concept, video slots have long been a source of entertainment in entertainment venues and online dating back 130 years. From winning a prize for lining up symbols’ slots are now mega money machines with some of them paying millions in prize money at land-based casinos or online.

What is interesting is how slots evolved. From one-armed bandits, to slots and fruit machines before they added TV screens, inevitably creating video slots. Next on the agenda was the internet where the names ‘online slot’ or ‘online video’ slots are now the most commonly used terms.

One-Armed Bandits

In the 19th century slots were one-armed bandits because you needed to pull a lever that would send the reels spinning. This early version of a slot game had 5-reels (not 3-reels as many believe), 1 pay line, and they were not there for people to win ‘cash’ but they won prizes instead. This is because at the time there was no dispenser for cash to drop into.

Sittman & Pitt, the inventor of the very first slot in 1891, did not yet include a coin slit. Someone would simply pay the barman or establishment owner to pull the ‘one arm’ lever which would spin 3 reels using playing card symbols. If alike symbols lined up on the middle pay line, then according to the card value, the player would win a prize such as free drink.

Back in these early days of slots were naturally random. There was no mechanical mechanism deciding on when the reels should stop, RNGs or provably fair algorithms. Much like a roulette wheel, players spin the reels, and the symbols landed in place naturally with no mechanical help.

The Liberty Bell

It was Charles Fey who first introduced a slot you could put a coin in back in 1895. He was also the person that reduced the reels from 5 to the classic 3-reel slot. In this version there were spades, diamonds, clubs, hearts, horseshoes, and finally the famous ‘Liberty Bell’—this was the original Liberty Bell slot machine. With only 3 reels and a defined set of symbols, the birth of automatic paying slot machines was here, and slots became a US phenomenon with the nickname one-armed bandit.

Fruit & Bar Symbols

The fruit symbol hit the slots market in 1907 when Herbert Mills invested in the ‘Operators Bell’ slot. The slot used classic fruits such as cherries, melons, and jackpot symbols. On top of this, Mills added the bar symbols!

Mechanical Slot Machines

Slots quickly developed, and rightly so because they were money spinning machines which they still are today. In 1963 they took a huge twist in the advancement of button play which would eventually push out Sittman & Pitt’s original one-armed bandit model.  

However, at this time the RTP on mechanical slots was still quite low at around 80% to 90% while according to, today’s video slots online have an average RTP of around 96%.

Soon there were multiple slot manufacturers and each one had their own ideas on how to keep the idea of slots gameplay fresh. Game boards with LED backlights become a new addition so the slots could use bonus features. Other features such as nudges, free spins, and skill stops were also added. 

All this new added fun and tech was possible because of the introduction of electronic game chips. These chips could control the randomness of spins, features, and bonus games.

Online Slots

The first online slot that came online legally that we know of was Cash Splash by Microgaming. This is a progressive jackpot slot game that still exists within the Microgaming progressive slots. It has been through several modifications since its first inauguration, but what an amazing claim to fame—a slot title that has been around since the beginning of online slots.

Today some of the most loved slots use HTML5 code, 3D graphics, and Disney quality animations along with numerous computer generated features such as NetEnt’s, and the online slot world’s, most popular video slot title Starburst!

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