In 1976 a small company called Fortune Coin took a 19-inch Sony Trinitron, modified it, and bolted it inside a slot cabinet for a trial run at a Las Vegas hotel casino. Nevada approved it, IGT bought the company two years later, and every screen-based slot since then has descended from a television in a box.
Charles Fey’s Liberty Bell, built in San Francisco at the end of the 1890s, set the three-reel, automatic-payout template, and Bally’s Money Honey made the machine electromechanical in the mid-1960s. Fortune Coin’s video machine was the real break, because the reels became frames drawn on a screen and the outcome became a number produced by software. Once the number and the picture are separate things, the picture can be drawn anywhere.
The first online casino software was a desktop download. Microgaming is usually credited with the first of it in 1994, and CryptoLogic’s platform with the first real-money wager online in 1996, and for the next decade or so the model was a Windows client you downloaded and patched. Browser play arrived through Flash in the 2000s, and Flash came with a ceiling: a plugin to install, and no route to phones at all. Steve Jobs’s 2010 letter put the objection in a sentence, saying Flash “was created during the PC era” and built for PCs and mice. The plugin never ran on iPhones, and Adobe ended support on December 31, 2020 and blocked Flash content from running on January 12, 2021. By then HTML5 had been a W3C Recommendation for six years, since October 2014.
HTML5 changed the economics more than it changed the games. A title written once against Canvas, WebGL and the Web Audio API runs on a phone, a tablet and a desktop without a separate port, and by the time Riot was putting Teamfight Tactics on phones in 2020, the slot studios had been mobile-first for about five years. Aggregation then piled the libraries up: Light & Wonder said in 2022 that its OpenGaming platform “delivers more than 2500 games from a global network of in-house and third-party game studios” through one integration, and once an operator plugs into a few aggregators it can stock thousands of near-identical five-by-three grids from studios a player has never heard of.
FreeSpins.US has free demos of about a thousand of them with the studio and its RTP listed for each, and that RTP is the studio’s default, which is not always what a casino runs. Push Gaming publishes Jammin’ Jars at 96.83% or 94.25% and notes that “RTP’s may vary per casino”; the operator picks which one it licenses, so a demo’s number is the top of the range, and two casinos can run the same title at different published returns.
The phone took HTML5 the rest of the way. Progressive web apps let a site sit on a home screen and behave like an install; Google describes the format as reaching “any web user on any device with a single codebase”, and Apple’s addition of Web Push for home-screen web apps in iOS 16.4 in early 2023 meant a casino site pinned to a home screen could do most of what an installed app did, including the push notification an operator once needed an App Store listing to send. The audience was already there. Evolution, the largest live-casino supplier, reported that 71% of its 2024 revenue came from mobile.
Graphics headroom kept growing as well. WebGPU shipped by default in Chrome 113 in May 2023 and reached Safari with version 26, giving browser games access to the GPU at close to native performance and, for the first time, first-class support for general computation on it rather than only drawing. For a slot that mostly means richer animation and steadier frame rates on a mid-range Android phone or an older iPhone, and a build that no longer has to be cut down to run in a tab.
What hasn’t changed is the audit underneath. In regulated US markets the random number generator is a tested component, and the best-known tester is Gaming Laboratories International, whose business, as it puts it, is to “test, review and report on gaming devices and systems against the standards established by relevant gaming jurisdictions worldwide”. Its GLI-19 standard for interactive gaming, current version July 2020, requires that the RNG used to determine outcomes “shall be cryptographically strong”, and it covers the rest of the platform too: player accounts, geolocation, and the record of every game played. Michigan writes it directly into its administrative code, rule R 432.633, and sends every platform to the board or an approved independent lab for certification before it goes live. New Jersey and Pennsylvania publish technical standards of their own on top of that, so a game sold into several states usually gets certified more than once.
Players must be 21 years of age or older or reach the minimum age for gambling in their respective state and located in jurisdictions where online gambling is legal. Please play responsibly. Bet with your head, not over it. If you or someone you know has a gambling problem, and wants help, call or visit: (a) the Council on Compulsive Gambling of New Jersey at 1-800-Gambler or www.800gambler.org; or (b) Gamblers Anonymous at 855-2-CALL-GA or www.gamblersanonymous.org.
