SteamOS is the operating system behind Valve Software's Steam gaming platform. The initial public version was SteamOS 1.0 "alchemist" beta. It was based on Debian 'wheezy' (stable 7.1) with some proprietary bits, and it was released December 14, 2013. SteamOS "brewmaster", based on Debian 8.1, was released June 25, 2015.