Valve

Valve was founded in 1996 by Gabe Newell and Mike Harrington, both formerly at Microsoft, and is based in Bellevue, Washington. Its first game, Half-Life, came out in 1998; Counter-Strike, Portal, Left 4 Dead, Team Fortress and Dota followed.

In 2003 it launched Steam, now the platform that connects thousands of developers and publishers with millions of players. Valve also builds hardware, including the Steam Deck and the Valve Index.

Valve describes itself as a flat company without job titles, hiring broadly skilled people rather than for fixed roles. It develops the Source engine and open-sources projects such as Proton, which runs Windows games on Linux and powers SteamOS.