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Slot machines are, without a doubt, the engine of the modern casino. The American Gaming Association just revealed that in January 2026 slot machines generated $3.01bn in revenue with table games adding $818.2m. In the online space, slots are the undisputed #1 category in the iGaming industry. But where did it all start? And how did we get from a mechanical contraption in a San Francisco saloon to the 117,649-ways Megaways titles spinning on our phones today?
Let's take a walk through the history of slot machines – a very interesting story.
The origins of the slot machine have their roots in the 1890s. In 1893, a Brooklyn company called Sittman and Pitt took out a patent on a coin-operated gambling machine based on poker: five drums, 50 card faces, one nickel to play. No automatic payout. If you landed a good hand, the bar/saloon owner handed you a prize – a beer, drinks, or a cigar. The drums could be rearranged, and two cards were quietly removed from the standard deck to tilt the odds in the house's favour.
Clever, but more like an “ancestor” of the slot machines. That distinction belongs to the man who brought automation and “liberty” into the mix.
Charles Fey was a German-born American mechanic from San Francisco. Somewhere between 1887 and 1895 he built the Liberty Bell slot machine: he brought simplicity and automation with just three spinning reels, five symbols (horseshoes, diamonds, hearts, spades, and a cracked Liberty Bell – an iconic symbol of American independence land namesake of the contraption), and an automatic payout mechanism.
Getting three Liberty Bells in a row was the Jackpot, earning you fifty cents – ten nickels.
Fey couldn't patent it because gambling was illegal in California, so competitors copied it freely – plus, the devices were banned after a few years in the state. However, his invention was so well-sought that Fey still could not keep up with the demand for them elsewhere.
One of the first imitators, the Herbert Mills "Operator Bell" (1907), introduced fruit symbols, cherries, lemons, oranges, as part of a gum-dispensing attachment. The BAR symbol we still see on classic slots today originated from the logo of the Bell-Fruit Gum Company.
Fey's design – three reels, automatic payouts, symbol-based wins – remains the structural DNA of every online slot you'll play today.
November 1963. Bally Manufacturing, a Chicago company better known for pinball machines, launched the Money Honey: the world's first fully electromechanical slot. It had a bottomless hopper, and it could pay out up to 500 coins automatically without an attendant. For the gambling industry at the time, this meant no more payout caps, nor calling someone over to verify a win.
The slot machine lever remained (players expected it by then) but it was decorative from day one. Electricity was doing all the work.
Within five years, Bally controlled 94% of the Las Vegas slot machine market. The electromechanical era also gave birth to the "nudge and hold" mechanics that was central to the British fruit machine culture: a direct result of UK gambling law requiring games to include an element of skill.
In 1976, Fortune Coin Co., a Las Vegas-based company, built the first video slot machine in California: they used a modified 19-inch Sony Trinitron TV as a display, with logic boards running the game. It debuted at the Las Vegas Hilton and spread across the Strip after it secured the Nevada State Gaming Commission approval. Fortune Coin was then acquired by IGT, which in 1986 launched Megabucks: the first wide-area progressive jackpot, linking machines across multiple casinos into one shared prize pool. In 2003, a Megabucks jackpot hit nearly $40 million.
Then came 1996, and WMS Industries' Reel 'Em In: the first video slot with a second-screen bonus round. A completely separate screen, triggered mid-game. That one mechanic is the direct ancestor of every bonus feature in every online slot today, while this type of machine had appeared in Australia since 1994.
By the late 1990s, slots were generating more than 70% of land-based casino revenue. The RNG (Random Number Generator) had replaced physical mechanisms entirely. This was the bridge to what came next.
In 1994, Microgaming built the software infrastructure for the first online casino. Slots made the jump to the internet almost immediately. The Free Trade & Processing Act (1994) passed by Antigua and Barbuda gave operators the legal framework to get licensed, and the online casino industry was open for business.
In 1998, Microgaming launched Cash Splash: the world's first online progressive jackpot slot. Then, in 2006, Mega Moolah launched. It earned the nickname "The Millionaire Maker" due to its track record of paying out record-breaking multimillion-dollar sums
The advantages of online slots over land-based were obvious: accessible from anywhere, available 24/7, lower costs, and an essentially unlimited library of themes and mechanics. Player numbers grew fast. The Unlawful Internet Gambling Enforcement Act – UIGEA (2006) in the United States complicated things and forced many operators out of the US market, but the global online slots industry kept expanding regardless.
The iPhone's arrival in 2007 changed everything – not just for slots, but for iGaming broadly. The industry rebuilt its entire game library in HTML5, the coding standard allowing casino games to run natively in any browser on any device. What had been a desktop experience became a handheld one. Today, mobile accounts for the majority of online slots traffic across most regulated markets.
This era also saw casino streaming culture take hold on Twitch, with streamers broadcasting their gameplay to thousands of live viewers. Developers started designing with streamability in mind: big moments, dramatic cascades, visually spectacular wins! Volatility became a marketing feature in its own right.
In 2016, Australian studio Big Time Gaming (BTG) released a slot called Dragon Born, introducing a mechanic called Megaways. This was the Megaways concept: instead of fixed paylines, the number of symbols on each reel changes randomly with every spin. Six reels, each showing 2 to 7 symbols. Multiply those numbers together and you get the ways to win for that spin: up to 117,649.
Bonanza Megaways, released later in 2016, is the game that turned the Megaways mechanic into a global phenomenon.. Cascading reels, free spins with progressive multipliers that don't reset between spins, shifting reel grid, and high-energy "Hillbilly" soundtrack .
BTG licensed the Megaways engine to other developers rather than keeping it exclusive. Blueprint Gaming, Red Tiger, Pragmatic Play, and dozens of others built their own Megaways titles. Evolution Group eventually acquired BTG in 2021 for approximately €450 million. The Megaways mechanic is now probably the most replicated format in online gaming.
The evolution hasn't stopped. Studios are experimenting with bonus buy features, Megaclusters, linked progressives, and VR environments. AI-driven personalisation is influencing game recommendations. Blockchain-based mechanics that pioneered in the crypto casino space are introducing new transparency into how outcomes are verified.
Responsible gambling tools like session time tracking, deposit limits, and affordability checks are also becoming standard features rather than optional extras across regulated markets. Through online slots and the evolution of iGaming, the slot machine has come a long way from Fey's iconic cast-iron cabinet. And it's still moving, setting new frontiers.