Valve Releases Team Fortress 2 Source Code to Empower Modding Community

The release allows creators to build new games based on TF2, with a non-commercial license ensuring mods remain free.

Valve has released the full client and server source code for Team Fortress 2, marking a significant update to the Source SDK.
The SDK enables modders to create entirely new games or modify TF2 extensively, beyond the capabilities of previous tools like the Steam Workshop.
Mods created with the SDK must be free and cannot profit from the work of Steam Workshop contributors, as stipulated by Valve's non-commercial license.
The move is seen as Valve passing the torch to the TF2 community, which has played a vital role in keeping the 18-year-old game alive and vibrant.
Alongside the SDK release, Valve has updated its multiplayer back-catalogue Source engine titles with improvements like 64-bit support and scalable UI.