PlayTribes was a planned browser-based version of Starsiege: Tribes, an online multiplayer first-person shooter developed by the now defunct Dynamix game studio in 1998 for the PC. InstantAction first announced PlayTribes in March 2009, along with their acquisition of the Tribes intellectual property. An open beta was scheduled to release that summer but was pushed back after Louis Castle came on board as their new CEO, and changed the focus of the company to develop a new game-embed platform. The game was shown off in September 2009 at PAX in a relatively playable state. On October 23, 2010, Hi-Rez Studios announced that they had bought the Tribes IP from InstantAction, which canceled any future development on PlayTribes.
A public beta for PlayTribes was originally announced in May 2009. As of March 2010, a version of PlayTribes (1.40.655) standalone executable has been leaked by an anonymous playtester of the beta and has been circulating throughout Tribes dedicated communities on the internet, such as TribalWar.