Development

Guild Wars is the first game created by developer ArenaNet. Senior developers from Blizzard Entertainment, some involved in the early development of World of Warcraft, left to create ArenaNet to develop a game which took risks with game design and business model. Guild Wars development was first announced in April 2003. Guild Wars Prophecies, initially marketed simply as Guild Wars, was released in April 2005. Sorrow's Furnace added further playable content to Prophecies in September 2005. Guild Wars Factions was released exactly a year after Prophecies in April 2006 followed six months later by Guild Wars Nightfall in October 2006. A fourth campaign was in development, but after reviewing feedback from fans and the sort of changes they wanted to make, ArenaNet elected to focus on an expansion pack, Guild Wars: Eye of the North, released in August 2007, and Guild Wars 2.

Guild Wars developement began in an environment following the release of EverQuest when a number of new MMORPGs were announced. ArenaNet positioned Guild Wars in a niche in this landscape, offering unlimited gametime without subscription fees. ArenaNet believed that players would not pay subscription fees for every online game they play and that paying a fee would cause players to make a "lifestyle commitment" to a particular game, rather than the usual behaviour of playing many different games and switching between the. Jeff Strain, a founder of ArenaNet, said, "It is our opinion that the free online gaming model combined with frequent content updates is the optimum online paradigm for interfacing with consumers and creating a significant, enduring gaming franchise."

ArenaNet has used open beta testing throughout the development of the Guild Wars series. For the first public appearance of Prophecies in April 2004, that occurred in conjunction with E3 2004, people were encouraged to download the client and play an online demo of the game to test its networking capabilities. This was followed by a preview event and several beta test weekend events. Both Factions and Nightfall had similar test weekends prior to their release. Nearly 500,000 players spent an average of 8.5 hours playing the Nightfall PvE content during its second beta test weekend. In addition to the public beta events, ArenaNet used continuously running closed alpha test servers throughout development; some alpha testers were ArenaNet employees but most were volunteers from the player community who signed a non-disclosure agreement with ArenaNet. After the release of Eye of the North, the bulk of the development and test teams were moved to the Guild Wars 2 project, though a small maintenance and QA team remains on the original Guild Wars project. The group of volunteer alpha testers was disbanded in January 2008, and no plans have yet been announced about repeating such an alpha test program for Guild Wars 2.

Aspects of every campaign have been influenced or modified based on feedback from the player community. Such changes began soon after the release of the original Prophecies, when, for instance, skill acquisition in the co-operative campaign was simplified, and PvP unlocks were made purchasable with the new mechanic of faction rewards for competitive victories. Although further playable content¡ªsuch as quests and missions¡ªare no longer expected for the original Guild Wars series, ArenaNet continues to make such changes to the gameplay elements and monitors game balance issues.

ArenaNet also continues to develop in-game events that generally coincide with real events such as Christmas, Hallowe'en, and the Chinese new year (for the Asian-influenced in-game continent of Cantha). These events feature minigames, quests, event-specific PvP gametypes such as dodgeball or beetle racing, special decorations for in-game outposts, and various in-game rewards such as masks and collectible gifts. Regular events also occur every weekend; each such event temporarily increases certain in-game rewards such as the drop rate of loot, reputation points for various in-game activities, or faction points.

 Game engine

The game engine for Guild Wars was developed by ArenaNet. Engine components developed for Guild Wars are available to be licensed to other NCsoft companies and have been used in other NCsoft games. However, ArenaNet have said they will not license the game engine technology to non-NCsoft companies.

 Content delivery and network architecture

To support their fee-free approach to online gaming the server architecture developed for the game was core to minimizing the bandwidth costs associated with maintaining game servers. Infrastructure design was influenced by the developers' experiences with Battle.net development.

The game client is available for download as a very small file. Each time there is an update to the game the existing client automatically downloads a new version of the client which examines a manifest of files to determine which files have been modified and therefore need to be downloaded to the client machine. This manifest is prioritized, the most important files are downloaded prior to the player being able to start the game, the rest are downloaded in the background while the player is playing. ArenaNet uses this rapid update technology to make changes on demand and close exploits in the system.

ArenaNet also utilizes their update technology to preload content from new Guild Wars campaigns onto existing players' accounts prior to the release of that campaign. The content is only activated after the right key is added to the player's account and the game servers allow the campaign changes to go live.

The game is server hosted. Much of the game mechanics are performed or verified by the game servers. The Guild Wars servers are set up in a distributed model. Players are presented with what appears to be a single server but their data is moved to different locations or servers depending on where in the world they are playing and server load at the time.