Katan.io is a free online multiplayer game inspired by the popular board game Settlers of Catan. Players take turns building settlements, roads, and cities on a randomly generated island. The goal of the game is to score the most points by collecting resources, trading with other players, and building development cards. Katan.io is a fast-paced and strategic game that can be played in a web browser. It is a great way to experience the classic Settlers of Catan game without having to own the physical board game.