A short history of multiplayer browser games: from text MUDs and Java applets to Flash, .io and WebGL

Browser games have existed in some form since the web opened up to the public in the 1990s, and the 2000s were a “golden age” for them, largely built on Adobe Flash.^[1] Multiplayer has been part of the story from the very start. Here is how it unfolded, with the games from that history you can still open today.

1. Text and tables (1995–2000)

The earliest browser games looked like text-based MUDs, because early browsers could do little more than render HTML.^[1] One of the first known examples, Earth 2025 (1995), was text only but let players interact and form alliances.^[1] That template (log in, spend your turns, check back tomorrow) is still alive: Hattrick has run since August 1997,^[21] Achaea since 1997,^[24] Utopia since 1998,^[25] and Kingdom of Loathing since 2003, funded by donations rather than ads.^[22]

The same year, Tom Fulp launched the site that became Newgrounds.^[3] Its 1999 Flash game Pico's School helped establish it as a “public force”.^[3]

2. Java applets and card rooms

Java applets arrived with the first version of Java in 1995 and let small programs run inside a web page through a browser plug-in.^[2] They powered the first big wave of real-time multiplayer: ClassicGames.com was created in 1997 to host Java-based multiplayer classics like chess and checkers, and its popularity led Yahoo to buy it and build Yahoo! Games, launched March 31, 1998.^[1][4] Pogo moved from a Windows executable to a browser-based Java applet in the same era.^[5]

The most famous Java browser game is RuneScape, released by Andrew Gower with his brother Paul on January 4, 2001 and initially run from the family home in Nottingham.^[6] The original version, later called RuneScape Classic, ran until August 6, 2018.^[6] Virtual pet site Neopets launched in 1999 too.^[7]

Applets did not last: browsers started phasing out NPAPI, the plug-in technology they relied on, in 2013, and by 2015–2017 applets could not run at all.^[2] Java deprecated them in Java 9 (2017) and removed them in Java 26 (2026).^[2] Board-game rooms like PlayOK and Yucata carry the card-room tradition on today.

3. The Flash golden age

Macromedia released Flash 1.0 in December 1996; ActionScript arrived with Flash 5 in 2000.^[8] Flash found its niche as the dominant platform for browser games, with portals like Newgrounds, Kongregate and Armor Games dedicated to hosting them.^[8] Kongregate launched on October 10, 2006,^[9] and Miniclip on March 30, 2001.^[19]

Flash also powered the era's big multiplayer worlds. Club Penguin began as a Flash 4 experiment in 2000 and opened to the public on October 24, 2005; Disney bought it in 2007.^[10] Transformice, a mouse-and-cheese physics platformer, launched on May 1, 2010^[26] and is still running.

4. Facebook and social network games

The 2000s also brought social network games.^[1] FarmVille launched on Facebook in 2009 as a Flash application and became the most popular game on the site, peaking at 83.76 million monthly active users in March 2010.^[11] It closed on December 31, 2020, the day Facebook stopped supporting Flash games.^[11]

5. Mobile and the end of plug-ins

Wikipedia credits two factors for the decline: the rise of mobile gaming, which accelerated with the iPhone in 2007, and Apple's 2010 announcement that its devices would not support Flash.^[1] Many developers moved to mobile.^[1] Adobe announced Flash's end of life on July 25, 2017 and discontinued Flash Player on December 31, 2020.^[18] Our Flash shutdown guide covers what happened next.

6. HTML5, WebGL and WebSockets

The replacement was the open web itself. The WebGL 1.0 specification, a JavaScript API for 2D and 3D graphics without plug-ins, was released in March 2011.^[12] Mozilla's BrowserQuest, built with Little Workshop, was a demonstration of the new stack: WebSockets for multiplayer, canvas for graphics, localStorage for saves, and a Node.js server.^[13] WebAssembly followed, first released in March 2017 and supported in all major browsers by November 2017.^[17] Today 3D multiplayer shooters like Krunker and Shell Shockers run straight from a web page with no plug-in.

7. The .io boom (2015–2016)

On April 28, 2015, Brazilian developer Matheus Valadares released Agar.io after sharing it on 4chan.^[14] It went viral and birthed a new genre of large-scale, arena-based browser games, many on the .io domain.^[16] Steven Howse's Slither.io followed on March 25, 2016 with servers for up to 500 players,^[15] and Valadares released Diep.io in mid-2016.^[23] Wikipedia notes .io games became popular again during the COVID-19 pandemic in 2020–2021, thanks to how easy they are to access.^[16] We track 55 games from this wave; see the best .io games still online.

8. Today

Browser games are now built with standard web technologies (HTML, CSS, JavaScript and WebAssembly), with WebGL and WebGPU for graphics.^[1] Old Flash content survives through emulators like Ruffle, which Newgrounds sponsors and uses.^[3][20] And the classics keep running: at our last sweep, 155 of the 157 games in this directory answered. Browse them on the timeline, or pay respects in the graveyard.