.io games are a genre of browser-based multiplayer games that are often characterized by the use of the .io top-level domain name. [1] [2]
Starting in mid-2016, soon after the popularity spikes of Agar.io and Slither.io , more games in the .io games genre began to be released. [1] [3] Many of these games were simple clones of popular games, usually released in a top down-format. [2]
Agar.io was announced on 4chan on 27 April, 2015 by Matheus Valadares, [4] a then 19-year-old Brazilian developer. In the game, players control one or more circular cells in a large map with many players, representing a Petri dish. The goal is to gain as much mass as possible by eating cells and player cells smaller than the player's cell while avoiding larger ones which can eat the player's cells. The game went viral on the free online games site Miniclip, and birthed a wave of new .io titles from around 2016—a new genre of large scale, arena based browser games. [5] [6] Slither.io , a free for all multiplayer game in the Snake genre was created in 2016 by Steven Howse, a self-taught independent developer who was inspired by Agar.io. The game would gain traction in the years following. The basic premise of the game has 50 players compete to eat colored orbs and grow as large as possible, while destroying other player's snakes. [7] [8]
During mid-2016, more games in the .io games genre began to be released. [1] [3] Many of these games were simple clones of popular games, usually released in a top down-format. [2] Some notable games released in this period include Diep.io (another game by Matheus Valadares), [9] ZombsRoyale.io , [10] Surviv.io , Shellshock.io, [11] Hole.io , and Snake.io . These games all remain popular and are some of the most played games in the .io games genre, but many websites still exist that use variations or ripoffs/clones like Cool Math Games.
.io games became very popular during the peak of the COVID-19 pandemic from 2020 to 2021, because of their accessibility on the web. Most games, not just .io games, however, also experienced growth during this time. [12] Since 2021, it has generally declined in popularity for various reasons, including lack of updates and the rise of mobile and video gaming. [13]