Online games started in the 1980s with MUDs, simple multiplayer text-based games, often played on a BBS using a modem. These games were frequently based on fantasy settings, using rules similar to those in the tabletop role-playing game Dungeons and Dragons. Other styles of games, such as chess, Scrabble clones, and other board games were available. Since continuous connectivity was often expensive as access was frequently charged on a per-minute basis, some games were set up as play-by-email games.

As the World Wide Web developed and browsers became more sophisticated, people started creating browser games that used a web browser as a client. Simple single player games were made that could be played using a web browser via HTML and HTML scripting technologies (most commonly JavaScript, ASP, PHP, and MySQL). More complicated games would contact a web server to allow a multiplayer gaming environment. The development of web based graphics technologies such as Flash and Java allowed browser games to become more complex. These games, also known by their related technology as "Flash games" or "Java games"), became increasingly popular. Many games originally released in the 1980s, such as Pac-Man and Frogger, were recreated as games that could be played using the Flash plugin on a webpage. Most browser games have limited multiplayer play, often being single player games with a high score list shared amongst all players.