Valve has opened up Team Fortress 2's full client and source code, encouraging players to 'change, extend, or rewrite' the game in any way they like. However, all mods must be released for free.

Later this year, the Team Fortress 2 Classic mod will arrive on Steam to let you step back in time to the early days of Valve’s class-based shooter, when it was more game than hat collection ...

Here’s how it works. It took almost 20 years, but Team Fortress 2, the team-based FPS that changed a great many lives when it debuted in 2007, now has an SDK that Valve says will enable creators ...

Why it matters: Team Fortress 2 launched 17 years ago but still receives significant updates, and its player base is as healthy as ever. The latest patch fully unlocks the game's SDK, releasing ...