IO games are free online games that you can play in real time on your web computer. Online gameplay is the thing that most io games are about. Aside from that, most of these games are built on the io domain extension, which stands for 'Indian Ocean.' Since "Input/Output," a familiar term in computing, is shortened to "IO," this top-level domain extension is popular with software engineers.
Agar io was the first io game. It was made by Matheus Valadares in 2015, and the internet forum 4chan helped it become very famous. The game is all about cells that grow when they eat agar and eat other players. A few months after the game came out, Miniclip bought it, and a new type of game based on the simple io name extension began to take shape.
The games that came after Agar io focused on the growth features that made it so popular, making it clear that io is not just a domain extension but also a genre. One of these games was Worms Zone, which was just like Worms but with snakes instead of worms. There are now many grow games like Snake io and Wormate that take this fast-paced survival idea even further.