An exciting game with spinning reels and colorful pictures has attracted many fans around the world for many years. Slot machines, nicknamed the ''one-armed bandits'' now have a digital alternative, namely, online slots. The predecessors of online slots were video slots, where for the first time a video screen appeared in the machine instead of a mechanical device with reels. In online slots, as well as in slot machines, the principle of a random number generator is based on the work. Thanks to him, a variety of combinations of pictures can appear on the screen, leading or not leading the player to win or receive bonuses.