Online casino games are slot and table games, such as roulette and blackjack, played on a phone or a website instead of in a casino. Where it is legal, people play them for real money. Elsewhere, the same games are played for fun, with coins that cannot be cashed out. Many of them are made by the same studios that make the slot machines on casino floors.
An online casino game involves two companies. The studio makes the game and runs it on its own servers. There, a random number generator decides each result, and the game is set to keep the house edge, just as on a machine. The online casino is the company that holds the player's account and her money. It shows games from many studios in one app. Each time the player spins, the casino's app sends the bet to the studio's server, and the server sends back the result. The studio is paid a share of what the casino keeps.
In India, online casinos played for money are banned. The Online Gaming Act 2025 bans all online games played for money. So these games are sold mainly abroad.
Take, for example, a player in Manchester, in Britain, where online casinos are licensed by the Gambling Commission, the British regulator. Before she can play, the casino must confirm her identity and that she is at least 18 years old, through identity verification (IDV). She deposits £20 with her debit card, through a payment gateway. In Britain, gambling with a credit card has been banned since 2020. She plays a slot game at 50p a spin. British rules now limit the stake on an online slot to £5 a spin, and to £2 a spin for players aged 18 to 24.
The casino must also watch how she plays. Say she plays for hours without a break, or deposits again and again after losing. Then the casino must step in, for example with a message on her screen or a phone call. These rules are part of responsible gambling.
A studio usually releases each game for fun as well, as a social casino game. In that version, players buy virtual coins that are never paid out. Some government lotteries also sell online instant-win games of the same kind, through their lottery systems.
Studios with engineers in Bengaluru make slot games played online, for real money and for fun, mainly for players in America and Europe.