The Source engine is a game engine developed by Valve Corporation, known for its advanced graphics and physics capabilities. It powers popular games like Half-Life 2, Counter-Strike: Source, and Portal. The engine supports various features, including realistic lighting, character animations, and complex environments, making it a versatile choice for game developers. First released in 2004, the Source engine has undergone several updates, enhancing its performance and expanding its tools for developers. It also includes the Source SDK, which allows users to create custom content and modifications, fostering a strong community of modders and enhancing the longevity of games built on the engine.