The VMF (Valve Map File) is a plain-text file format used by Valve Corporation's Source engine to store level design data for video games like Half-Life 2, Team Fortress 2, Counter-Strike: Source, and Portal. Unlike the compiled BSP (Binary Space Partitioning) files that the game engine directly reads for performance, the VMF file serves as the human-readable source file created and edited within the Hammer Editor, which is the official level design tool for the Source engine. A VMF file contains all the geometric information, entity placements (like spawn points, lights, triggers, and interactive objects), texture assignments, and brush definitions that constitute a game level. It is structured using key-value pairs and hierarchical blocks to define the world geometry (brushes) and the placement of game logic entities. Because it is text-based, modders and level designers can inspect, manually edit, and version control map changes relatively easily before compiling the map into the final, optimized BSP format required for gameplay.