# Browser game

A browser game is a video game that is played via the internet using a web browser. They are mostly free-to-play and can be single-player or multiplayer. Alternative names for the browser game genre reference their software platform used, with common examples being Flash games and HTML5 games.
Some browser games are also available as mobile apps or PC games, or on consoles. For users, the advantage of the browser version is not having to install the game; the browser automatically downloads the necessary content from the game's website. However, the browser version may have fewer features or inferior graphics compared to the others, which are usually native apps. Browser games also had a huge influence on independent video games.
The front end of a browser game is what runs in the user's browser. It is implemented with the standard web technologies of HTML, CSS, JavaScript, and WebAssembly. In addition, WebGL and WebGPU enable more sophisticated graphics. On the back end, numerous server technologies can be used.
Most browser games were originally created with Adobe Flash, but as Adobe Flash was shut down on December 31, 2020, special browser plug-ins are now required. Thousands of these games have been preserved by the Flashpoint project. The emulation plug-in Ruffle aims to continue browser accessibility of Flash games.

## Early browser games

When the Internet first became widely available and initial web browsers with basic HTML support were released, the earliest browser games were similar to text-based Multi-User Dungeons (MUDs), minimizing interactions to what implemented through simple browser controls but supporting online interactions with other players through a basic client–server model. One of the first known examples of a browser game was Earth 2025, first released in 1995. It featured only text but allowed players to interact and form alliances with other players of the game.

## The Flash era

Browser technology quickly began to mature in the mid-1990s with support for browser plug-ins and the introduction of JavaScript. More advanced browser interactions, unbounded by the restrictions of HTML and that used client-side processing were possible. Among other browser extensions, these new plug-ins allowed users to run applets made in the Java language and interactive animations created in Macromedia Flash. These technologies were initially intended to provide web page developers tools to create fully immersive, interactive websites, though this use fell out of favor as it was considered elitism and broke expected browsing behavior. Instead, these technologies found use by programmers to create small browser games among other unexpected uses such as general animation tools.
Sites began to emerge in the late 1990s to collect these browser games and other works, such as Sun Microsystems' HotJava. These sites started to become a popular commodity as they drew web visitors. Microsoft acquired one such site, The Village, in 1996, and rebranded it as the Internet Gaming Zone, offering various card and board browser games. ClassicGames.com was created in 1997 to host a selection of classic, Java-based online multiplayer games such as chess and checkers; its popularity led Yahoo! to purchase the site in 1998 and rebranding it as Yahoo! Games.
In 1999, Tom Fulp kickstarted the Flash games scene with the release of the game Pico's School on his site Newgrounds that featured a "complexity of design and polish in presentation that was virtually unseen in amateur Flash game development" of the time.
Many Flash games in the late 1990s and early 2000s received attention through the use of shock comedy or real-world events, like McDonald's Videogame, a satire of McDonald's' business practices, or Darfur is Dying, about the War in Darfur, Sudan. In 2017, Julie Muncy writing for Wired said, "Flash games lent themselves to the exaggerated and cartoonish, a style that eventually evolved into an affection-at least amongst its best creators-for beautiful grotesquerie. Like much of the younger gaming internet, Flash games defined boundaries simply to cross them; the best titles straddled a weird line between innocence and cruelty, full of gorgeous gore and enthralling body horror". In Pico's School, based on the Columbine shootings, the player must take down a goth school shooter. There are a few other controversies involving browser games and real-world events, such as the 2007 Virginia Tech shooting reenactment V-Tech Rampage, and NRA CEO Wayne LaPierre targeting the game Kindergarten Killers after the 2012 Sandy Hook shootings.
Expansion of broadband connectivity in the early 2000s drew more people to play browser games through these sites, as well as added attention as viral phenomenon. New sites like Kongregate and Armor Games arose for hosting Flash-based games while also offering their own titles, while companies like PopCap Games and King launched their own portals featuring titles they had developed. Social media sites also drove more players to browser games. Facebook, after launching in 2004, added support for browser game functionality that integrated with its social network features, creating social network games, notably with Zynga's Farmville. The success of browser games did hurt some developers. Humongous Entertainment reported that they lost players to Flash games in the early 2000s.
Flash games were considered to have hit their peak in the mid-2000s but waned by the early 2010s. Their popularity had fallen due to two primary causes. First was the introduction of mobile gaming, primarily with Apple's iPhone release in 2007 and the availability of the App Store. Through the App Store, anyone could release apps for the iPhone, and with the addition of in-app purchases, new revenue models such as free-to-play quickly emerged for mobile games, well surpassing the current ad-driven revenue model of browser games. Google used the same concepts for developing the Android storefront Play Store. Developers either augmented browser games or shifted to the mobile platform to take advantage of the new revenue opportunities; notably, King transitioned one of its browser games into one of the most successful mobile games, Candy Crush Saga. The second factor came from the claimed "death knell" for Adobe Flash by way of Steve Jobs' open letter to Adobe in 2010, stating that Apple would not support Flash on the iPhone platform due to security concerns and other factors. About a year after Jobs' letter, Adobe announced it would start deprecating Flash and transition users to HTML5 and other open standards in its other products. Adobe completely shut down Flash by January 12, 2021 after giving web developers a few years to prepare for this event. With little future in Flash, developers moved away from the browser platform in the mid-2010s.
As for Adobe Flash games, various collections of such games can be found. Even though Adobe Flash is "broken" and hard to launch after 2021, one can use alternatives, such as the Flashpoint Archive.

### Indie games

Browser games were an important platform for the emergence of indie games. In the late 1990s and early 2000s, the video game industry had started to coalesce around triple-A development, games made by large studios with multi-million dollar budgets. Because of the money involved, the industry took few risks in these major titles, and experimental games were generally overlooked. Browser games gave a venue for such titles during the early 2000s, and the broader interest in-browser games by the mid-2000s highlighted several of these titles. Subsequently, a number of early indie games are those based on browser games, such as The Behemoth's Castle Crashers, inspired by Newgrounds' Alien Hominid and Edmund McMillen's Super Meat Boy based on his Meat Boy browser game. Other indie developers got their start in browser and Flash games, including Vlambeer, Bennett Foddy, and Maddy Thorson.

## Post-Flash browser games

Post-2010, browser games written in other formats besides Flash remain popular, such as HTML5, WebGL, and WebAssembly. The .io domain, which was first used in 2015 by Agar.io, has become a popular domain attached to browser games, because of its short length, the ease of acquiring the domain, and the association with programming because "io" can also stand for input/output. Subsequently, these game developers have found ways to monetize their work by creating versions for mobile devices or other platforms which they can sell.

### .io games

.io games or IO games are a genre of free, online multiplayer that gained popularity with the success of Agar.io in 2015. The games are usually characterized by simple graphics and gameplay in a free for all multiplayer arena. The term ".io" comes from the .io domain, which was originally assigned to the British Indian Ocean Territory but became popular for game developers due to its short and memorable nature.
Thousands of .io games exist, and many of them have been subject to controversy for both political use and lack of moderation.

#### Agar.io

Agar.io is considered the first ever .io game. The game was announced on 4chan on 27 April, 2015 by Matheus Valadares, a then 19-year-old Brazilian developer. In the game, players control one or more circular cells in a map 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.
Agar.io went viral, and was featured on the free online games site Miniclip. The mobile version of Agar.io for iOS was released on 8 July 2015 and Android on 7 July 2015 by Miniclip. The browser version was released in June 2015 by CrazyGames. The YouTuber PewDiePie created a video titled "REDDIT WANTS TO EAT ME! (Agario Part 1) | PewDiePie," which has over 8.5 million views as of July 2024. The creation and quickly-growing popularity of Agar.io led to the creation of similar games using the .io domain, and eventually the .io game genre.

#### Slither.io

Slither.io was the second .io game to be released, which is a free for all multiplayer game that is in the Snake genre. 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. The game was created in 2016 by Steven Howse, a self-taught independent developer who was inspired to make it after playing Agar.io. The game quickly rose to be the top game on many platforms.

#### .io games as a genre

Starting in around 2016, soon after the popularity spikes of Agar.io and Slither.io, more games in the .io games genre began to be released. Many of these games were simple clones of popular games, usually released in a top down-format. Some notable games released in this period include Diep.io (another game by Matheus Valadares), ZombsRoyale.io, Krunker.io, Wings.io, Surviv.io, Hole.io, and Snake.io. These games all remain popular and are some of the most played games in the .io games genre.

#### COVID-19

During COVID-19, .io games became very popular because of their accessibility on the web. Most games, not just .io games, however, also experienced growth during this time.