Atmosphere came as two stand-alone applications: the Builder, which was used to build online "worlds", and the Player, which allowed users to explore these worlds. (In 3D Anarchy, these components were called Editor and Chat, respectively.) In addition to these applications, Adobe provided a browser plugin, to explore these worlds within a web browser, and a companion chat server called Adobe Community Server, which ran on an IRC-like protocol known as Yet Another Chat Protocol (YACP). During beta-testing, all three components of Atmosphere were available free of charge. Adobe distributed the server software under the "Atmosphere Open Source License", a permissive open source license.