A .io game or io game (pronounced dot eye-oh or eye-oh) is a type of free web browser game. Powerline.io is an io game.
.io games are a type of free web browser game whose web address ends in ".io" (hence its name). Io games are typically massive multiplayer online (MMO) action games.
.io games are forms of browser games have become popular in recent years. Popularity spiked after 2015's Agar.io, which led to other io games. Today, some of the most popular io games are Agar.io, ShellShock.io, Surviv.io, Paper.io, and of course, Powerline.io.
There are many io game developers. Andre Almeida is a notable example, as he developed several popular .io games including Wings.io, Brutal.io, and Powerline.io.